Torquing screw and fastener

Abstract

The present application relates to a kind of rotary cutting type fixed torque bolt and fastener, it relates to fastener technical field, including cutting bolt, retainer ring and cutting cover, cutting bolt includes head, screw rod and boss, boss is provided with mark, at least two outwardly protruding rotary cutting head are provided along the circumferential direction of mark;Cutting cover includes cover body and shielding portion, cover body is structured with wrenching structure, light hole is structured in cover body, shielding portion corresponds the center of light hole, shielding portion is connected to cover body by at least two frangible arms, the insertion hole for rotary cutting head insertion is formed between adjacent two frangible arms;Cutting cover is set on boss, rotary cutting head is inserted into insertion hole, shielding portion covers mark, retainer ring is arranged between boss and cutting cover, for preventing cutting cover from falling off, cutting cover is contacted and extruded rotary cutting head by frangible arm, to transmit torque;The present bolt, calculation and design process are simpler, not only can more accurately control the pre-tightening force of bolt connection, but also more convenient to realize mass production in industry.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of fasteners, in particular to a rotary cutting type torque fixing bolt and fastener. BACKGROUND

[0002] In the fields of building structures, equipment manufacturing, pipeline supports, etc., the connection of main structural components mainly adopts several forms such as bolt connection, welding, riveting, etc. The bolt connection is a detachable connection mode that uses bolts, nuts and washers to fasten and combine two or more parts (or components or parts) together. The core principle is to generate clamping force through the thread engagement of the bolt and the nut, so that the connected parts are tightly fitted, thereby realizing the transmission of force or the fixation of position. The bolt connection has the advantages of simple operation, reliable connection, accurate assembly, low cost, and no deformation of the connected parts, and is most widely used in daily life and industrial production and manufacturing.

[0003] When a bolt connection is used in a stressed connected component, the pre-tightening force of the bolt is an important technical index. In actual application, if the bolt connection does not reach the designed pre-tightening force, serious quality problems will often occur, affecting the safe operation and structural safety of the equipment, and even causing serious safety accidents. In order to ensure that the pre-tightening force of the bolt connection meets the requirements, in the traditional technology, the operator usually uses an electric torque wrench to tighten the bolt, and after tightening, the bolt that meets the specified pre-tightening force is marked with red paint; later, the inspector judges whether the bolt is tightened according to the requirements (that is, whether it meets the specified pre-tightening force) by observing whether the bolt is marked; the advantage of this method is that the inspection is intuitive and simple, and the disadvantage is that it relies too much on the self-consciousness of the operator, especially in the construction industry where temporary workers are widely used, which has a great risk, and marking itself also greatly increases the workload, in addition, the electric torque wrench is high in cost, and the size of the electric torque wrench is relatively large, which cannot be used in places with narrow operation space. In order to solve the deficiencies of the traditional technology, Chinese patent CN108006043B discloses a constant torque fastener, which comprises a bolt and a torque-limiting nut, the bolt comprises a bolt body, the bolt body comprises a head, a first screw rod and a second screw rod, the end of the second screw rod is provided with a protruding part; the torque-limiting nut is configured to fit the second screw rod, so that the torque-limiting nut can be threadedly connected to the second screw rod; at the same time, the length of the external thread in the second screw rod is configured to be greater than the length of the internal thread in the torque-limiting nut, so that the protruding part can extend from one end of the torque-limiting nut to the other end, so that the inspector can see the mark on the protruding part; at the same time, the torque-limiting nut is also provided with a vulnerable part, which is arranged in the axial direction of the threaded hole, so as to block the relative movement of the second screw rod. In actual use, the torque-limiting nut is first threadedly connected to the second screw rod, and the tightening personnel drives the entire bolt to rotate through the torque-limiting nut in order to gradually tighten the bolt, rather than driving the entire bolt to rotate through the head in the bolt; during this process, the protruding part at the end of the second screw rod is in contact with the vulnerable part, and as the pre-tightening force of the bolt increases, the extrusion force between the vulnerable part and the protruding part also increases, when the vulnerable part is damaged by the end of the second screw rod, the bolt connection just reaches the required pre-tightening force value, which can effectively ensure the pre-tightening force of the bolt connection, and when the pre-tightening force is reached, the mark on the protruding part is just exposed, so that the inspector can check, thereby effectively solving the drawbacks of the traditional technology.

[0004] Because the constant torque fastener in the process of tightening, the fastening personnel through the wrench tool (such as wrench) rotates the constant torque nut, the constant torque nut drives the bolt to rotate through the cooperation of internal and external threads, and the extrusion force between the protruding part and the vulnerable part is gradually increased, until the vulnerable part is damaged by the protruding part; In the design stage of the constant torque fastener, the parameters of the vulnerable part need to be accurately calculated and designed to achieve the effect that the bolt connection reaches the required pre-tightening force value when the vulnerable part is damaged; Because the constant torque nut is threadedly connected with the second screw rod, the threaded connection has frictional resistance, and when calculating the jacking force borne by the vulnerable part, the frictional resistance between the constant torque nut and the second screw rod due to the threaded connection needs to be deducted, but in actual application, it is found that with the increase of the pre-tightening force in the threaded connection, the frictional resistance between the constant torque nut and the second screw rod is also increasing, that is, the frictional resistance between the constant torque nut and the second screw rod is also a variable, at the same time, in the actual production and manufacturing process, it is difficult to accurately control the machining precision of the internal and external threads, so that the frictional resistance between the constant torque nut and the second screw rod is difficult to control strictly the same, on the one hand, it is difficult to accurately calculate the jacking force borne by the vulnerable part in the design stage of the constant torque fastener, and it is difficult to accurately design the parameters of the vulnerable part, so it is difficult to ensure that the bolt connection reaches the required pre-tightening force value when the vulnerable part is damaged, so as to achieve the purpose of accurately controlling the pre-tightening force; On the other hand, it leads to the need for a large amount of and complex calculation in the design stage of the constant torque fastener, which significantly increases the cost, thereby making it difficult for the constant torque fastener to realize mass production in industry; In addition, it also leads to more laborious fastening process of the constant torque fastener, which needs to be solved urgently. SUMMARY

[0005] The first aspect of the present application solves the problems of the existing constant torque fastener, such as inconvenient design, difficult mass production in industry, and difficult accurate control of pre-tightening force, and provides a rotary cutting type constant torque bolt with a simpler calculation and design process, which not only can more accurately control the pre-tightening force of the bolt connection and ensure the reliability of the bolt connection, but also is more convenient for production and manufacturing, and is very convenient for mass production in industry.

[0006] A kind of rotary cutting type fixed torque bolt, including cutting bolt, stop ring and cutting cover, the cutting bolt includes bolt body, bolt body includes head and the screw rod connected to the one end of head, screw rod is configured with external thread, the other end of head is configured with boss, the end of boss is provided with mark, at least two outwardly protruding rotary cutting heads are provided along the circumferential direction of mark;The cutting cover includes cover body and shielding part, the outside of cover body is configured with wrenching structure, the light hole of cover body is configured with the boss of adaptation, shielding part is set at the position corresponding to the center of light hole, shielding part is connected to cover body by at least two frangible arms, the insertion hole for rotary cutting head insertion is formed between adjacent two frangible arms;Cutting cover is sleeved on boss, rotary cutting head is inserted into insertion hole, shielding part shields the mark, stop ring is arranged between boss and cutting cover, for preventing cutting cover from falling off, cutting cover is contacted and extruded rotary cutting head by frangible arm, to transmit torque.In the scheme, by configuring stop ring, and setting stop ring between boss and cutting cover, so that stop ring is limited and constrained to boss, cover body is limited and constrained to stop ring, stop ring is limited and constrained to boss, so that cutting cover can be limited and constrained to boss by stop ring, effectively solve the problem that cutting cover moves along the axial direction of boss and falls off, and stop ring does not limit the rotation of cutting cover relative to boss, so that at least after frangible arm is pressed off, cutting cover has the freedom of rotation relative to boss, so as to facilitate to reduce the resistance of cutting cover, so that more torque is directly applied to frangible arm, which is beneficial to more labor-saving to press off frangible arm.By setting a convex column on the head of the cutting bolt, and constructing at least two outward convex rotary cutting heads at the end of the convex column, and arranging each rotary cutting head in the circumferential direction, at the same time, setting a shielding part in the cover body of the cutting cover, and connecting the shielding part to the cover body through at least two vulnerable arms, so that the insertion hole for the rotary cutting head is formed between the adjacent two vulnerable arms, after assembly, the cutting cover is constrained to the convex column through the stop ring, and each rotary cutting head is inserted into the corresponding insertion hole, in use, the cutting cover is rotated by the tool, the vulnerable arm of the cutting cover contacts and extrudes the corresponding rotary cutting head to transmit the torque, so that the whole cutting bolt and the cutting cover are driven to rotate synchronously through the cooperation of the vulnerable arm and the rotary cutting head, so that the rotary cutting type torque limiting bolt is gradually tightened, the extrusion force between the rotary cutting head and the vulnerable arm gradually increases, because the force is mutual, the extrusion force (or called force) borne by the vulnerable arm also gradually increases synchronously, when the extrusion force borne by the vulnerable arm reaches the limit, the vulnerable arm will be cut or pressed off by the rotary cutting head, therefore, on the one hand, through reasonable calculation and design of the parameters of the vulnerable arm, the vulnerable arm can be cut or pressed off when the rotary cutting type torque limiting bolt reaches the required pre-tightening force, so as to achieve the purpose of accurately controlling the pre-tightening force; on the other hand, in this process, because the cutting cover and the cutting bolt are not threadedly connected, and the friction force between the cutting cover and the convex column and the stop ring is a fixed value which is relatively small and basically unchanged, and the torque borne by the cutting cover directly acts on each rotary cutting head after overcoming the fixed friction force, therefore, when calculating and designing in the early stage, the resistance change and uncertainty brought by the thread connection do not need to be considered, so that the design and calculation process is simpler and more accurate, the pre-tightening force of the bolt connection can be more accurately controlled, and the production and manufacturing are facilitated, so that it is very beneficial to realize mass production in industry. By setting a mark at the end of the convex column, the mark is used to identify that the bolt has been tightened, that is, the pre-tightening force in the bolt connection reaches the required pre-tightening force value; at the same time, the cutting cover is provided with a shielding part, the shielding part is connected to the cover body through the vulnerable arm, at the beginning, the shielding part is in a state of completely shielding the mark, when the vulnerable arm is cut or pressed off, the shielding part automatically falls off due to the loss of support, so that the mark is automatically exposed, playing the role of identification, indicating that the rotary cutting type torque limiting bolt has reached the required pre-tightening force value, when the inspector inspects the fastening condition of the bolt, the conspicuous mark in the bolt connection can be used to judge that the bolt has been fastened according to the requirements, effectively solving the drawbacks existing in the traditional technology.

[0007] Further, one side of the vulnerable arm is configured with a pressure receiving surface, one side of the rotary cutting head is configured with a pressure applying surface matching the pressure receiving surface, the pressure receiving surface and the pressure applying surface are both configured as planes, and the rotary cutting head and the vulnerable arm transmit the force through the contact between the pressure applying surface and the pressure receiving surface. In this scheme, the rotary cutting head and the vulnerable arm transmit the force through the contact between the pressure applying surface and the pressure receiving surface, which is the force transmission between planes, thus making it easier to calculate the pressure borne by the vulnerable arm, which not only further simplifies the calculation amount in the design stage, but also makes the calculation result more accurate and more in line with the actual situation, thus achieving the purpose of more accurate control of the pre-tightening force.

[0008] The second aspect of the present application aims to solve the problem of more accurate control of the pre-tightening force, and further, the pressure receiving surface is coplanar with the central axis of the cover body, and the pressure applying surface is coplanar with the central axis of the convex column. In this scheme, by configuring the pressure receiving surface to be coplanar with the central axis of the cover body, the rotation direction of the pressure receiving surface is perpendicular to the rotary cutting head; by configuring the pressure applying surface to be coplanar with the central axis of the convex column, when the pressure receiving surface contacts and presses the pressure applying surface, the pressure borne by the pressure receiving surface is exactly perpendicular to the pressure receiving surface, forming a positive vertical pressure, which not only further simplifies the calculation and greatly reduces the calculation amount in the design stage, but also makes the calculation result more accurate, thus making it easier to accurately control the structure and / or material of the vulnerable arm, so that when the vulnerable arm is cut or broken by the rotary cutting head, the pre-tightening force between the cut bolt and the nut exactly reaches the required pre-tightening force value, thus achieving the purpose of more accurate control of the pre-tightening force.

[0009] Preferably, the outer side of the convex column is configured as a cylindrical shape, the convex column is coaxial with the screw rod, the light hole is configured as a circular hole, and the outer diameter of the convex column is smaller than the inner diameter of the cover body. This is to more stably set the cut-off cover in the cut-off cover and facilitate the rotation of the cut-off cover relative to the convex column.

[0010] Preferably, the insertion hole is configured as an arc structure, the rotary cutting head is configured to match the arc structure of the insertion hole, and the central angle of the rotary cutting head corresponding to the center of the convex column is greater than the central angle of the insertion hole corresponding to the center. By configuring the insertion hole and the rotary cutting head as arc structures that match each other, it is not only very simple to press the vulnerable arm by rotating the rotary cutting head, but also easier for the vulnerable arm and the rotary cutting head to form a transmission fit; this not only makes it easier to insert the rotary cutting head into the corresponding insertion hole, achieving faster and more efficient assembly, but also gives the cut-off cover the freedom to rotate relative to the convex column before the vulnerable arm is cut or broken.

[0011] Preferably, the wrenching structure includes six planes configured on the outer side wall of the cover body, and the six planes form a hexagonal structure. This is to match common wrenching tools.

[0012] Further, the vulnerable arm is configured with a vulnerable part, which comprises a hole or a slot. By configuring the vulnerable part on the vulnerable arm, the strength and rigidity of the vulnerable arm are reduced, so that the vulnerable arm meets the required pre-tightening force requirement.

[0013] Further, the outer side surface of the convex column is configured with a first annular clamping slot, and the inner side wall of the cover body is configured with a second annular clamping slot; the retreat stop ring is limited and constrained in the first annular clamping slot, and the cut-off cover is limited and constrained in the retreat stop ring through the second annular clamping slot; at least after the vulnerable arm is cut off by the cutting head, the cut-off cover can rotate relative to the convex column. In this scheme, through the limiting cooperation of the retreat stop ring with the first annular clamping slot and the second annular clamping slot, the cut-off cover is not easy to move along the axial direction of the convex column, thereby facilitating the prevention of the cut-off cover from falling off the convex column.

[0014] The third aspect of the present application aims to solve the problems of traditional retreat stop rings, such as assembly difficulty and large frictional resistance. Further, the retreat stop ring comprises a ring body and a second elastic clamping part adapted to the second annular clamping slot, the second elastic clamping part is arranged on the ring body and protrudes outward from the outer surface of the ring body, and the second elastic clamping part can be elastically deformed; the retreat stop ring is sleeved on the outer side of the convex column and is limited and constrained in the first annular clamping slot, the cut-off cover covers the retreat stop ring, and the second elastic clamping part is clamped in the second annular clamping slot. In this scheme, by arranging the second elastic clamping part capable of being elastically deformed on the ring body, the second elastic clamping part cooperates with the second annular clamping slot, so that the limiting cooperation between the second elastic clamping part and the second annular clamping slot can effectively prevent the cut-off cover from falling off; and during assembly, the second elastic clamping part can be automatically clamped into the second annular clamping slot, thereby enabling the assembly work to be very simple and efficient. In addition, since the second annular clamping slot is annular and the second elastic clamping part is clamped in the second annular clamping slot, the cut-off cover can rotate relative to the convex column under the action of an external force without considering the blocking of the vulnerable arm, thereby effectively meeting the action requirement of cutting off the vulnerable arm and reducing the frictional resistance of the cut-off cover, so that the tightening process of the bolt is more labor-saving.

[0015] Preferably, a plurality of second elastic clamping parts are arranged along the circumferential direction of the ring body; and the second elastic clamping part adopts a sheet-shaped elastic sheet structure.

[0016] Preferably, the number of the second elastic clamping parts is 3-6.

[0017] Preferably, the retreat stop ring is an integrally formed component.

[0018] To solve the problem that the stop ring is limited and constrained in the first annular clamping groove, in some solutions, the side wall of the ring body is configured with a fracture, the inner diameter of the ring body is smaller than the outer diameter of the convex column, the width of the first annular clamping groove is greater than or equal to the width of the ring body, and the ring body is limited and constrained in the first annular clamping groove. By configuring the fracture, the ring body is sleeved on the convex column, and by limiting the size of the ring body, when assembled, the stop ring can be clamped into the first annular clamping groove and limited by the first annular clamping groove, so that the purpose of limiting and constraining is achieved.

[0019] To solve the problem of more convenient, labor-saving and efficient installation of the cut-off cover, further, the inner side wall of the light hole is further configured with an annular mounting groove for accommodating the ring body, the lower end of the annular mounting groove penetrates the lower end of the cover body, and the second annular clamping groove is configured on the side wall of the annular mounting groove; the stop ring further comprises a first elastic clamping portion provided on the ring body, and the first elastic clamping portion is concave to the inner surface of the ring body; in the direction away from the head portion, the distance between the first elastic clamping portion and the ring body gradually increases, and the distance between the second elastic clamping portion and the ring body gradually decreases; the ring body is arranged in the annular mounting groove, the first elastic clamping portion is clamped in the first annular clamping groove, and the second elastic clamping portion is clamped in the second annular clamping groove. In this solution, by arranging the first elastic clamping portion and the second elastic clamping portion on the inner side and the outer side of the ring body respectively, and the directions of the first elastic clamping portion and the second elastic clamping portion are opposite, when assembled, by inserting the ring body into the annular mounting groove, the second elastic clamping portion can be automatically clamped into the second annular clamping groove, by covering the cut-off cover on the convex column and moving the cut-off cover in the direction close to the head portion, the first elastic clamping portion can be automatically clamped into the first annular clamping groove, not only the purpose of more convenient and efficient installation of the cut-off cover can be achieved, but also the frictional resistance of the cut-off cover can be further significantly reduced, so that the tightening process of the bolt is more labor-saving, especially in the case of manual tightening.

[0020] Preferably, a plurality of first elastic clamping portions and a plurality of second elastic clamping portions are arranged in the circumferential direction of the ring body, and the first elastic clamping portions and the second elastic clamping portions are arranged alternately.

[0021] Preferably, the first elastic clamping portion is a spring sheet, and the second elastic clamping portion is a spring sheet.

[0022] A fastener comprises a nut and the torque-limiting bolt, and the nut is threadedly connected to the screw rod.

[0023] Compared with the prior art, the torque-limiting bolt and the fastener provided by the application have the following beneficial effects:

[0024] (1) The calculation and design process of bolt connection is simpler, the pre-tightening force of bolt connection can be more accurately controlled to ensure the reliability of bolt connection, and the production and manufacturing are more convenient, which is very convenient for mass production in industry.

[0025] (2) in the process of tightening the bolt by the operator, when the set pre-tightening force of the bolt connection is reached, the easy-to-damage arm will be cut off or broken by the rotary cutting head, the cut-off cover can rotate relative to the cut-off bolt, the purpose of constant torque is achieved, at the same time, the shielding part can be smoothly detached from the cut-off cover, so that the mark shielded by the shielding part is exposed, the identification function is achieved, not only the drawbacks of the bolt inspection in the prior art can be avoided, but also the bolt inspection process is very simple, convenient, efficient and safe, and the missed inspection situation is not easy to occur.

[0026] (3) in the process of tightening, the required pre-tightening force can be achieved without using special tools, on the one hand, the use cost can be effectively reduced, on the other hand, the drawbacks that the special tools cannot be applied in some space-constrained occasions are solved, so that the use range of the bolt connection with pre-tightening force requirement can be improved. BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the embodiments will be briefly introduced as follows.

[0028] Figure 1 It is a structure schematic view of the cut-off bolt provided in the embodiments of the present application.

[0029] Figure 2 It is a structure schematic view of the cut-off bolt provided in the embodiments of the present application. Figure 1

[0030] Figure 3 It is a structure schematic view of the cut-off cover provided in the embodiments of the present application.

[0031] Figure 4 It is a top view of the cut-off cover. Figure 3

[0032] It is a sectional view of A-A in the cut-off cover. Figure 5 Figure 4

[0033] Figure 6 It is a structure schematic view of the stop ring provided in the embodiments of the present application.

[0034] Figure 7 It is a half sectional view of the stop ring shown in the cut-off bolt. Figure 6

[0035] Figure 8 It is a top view of the rotary cutting type constant torque bolt provided in the embodiments of the present application; in order to distinguish, the end of the rotary cutting head is coated in gray.

[0036] Figure 9 ​​​​It is a front view of a rotary cutting type fixed torque bolt provided in an embodiment of the present application; for the convenience of distinction, the end of the rotary cutting head is coated in gray.

[0037] Figure 10 It is a front view of a rotary cutting type fixed torque bolt provided in an embodiment of the present application; for the convenience of distinction, the end of the rotary cutting head is coated in gray. Figure 8 It is a partial sectional view at B-B in FIG. 1, in which the shielding part is not detached.

[0038] Figure 11 It is a front view of a rotary cutting type fixed torque bolt provided in an embodiment of the present application; for the convenience of distinction, the end of the rotary cutting head is coated in gray. Figure 10 It is a schematic view after the detachment of the shielding part.

[0039] Figure 12 It is a schematic view of another structure of a cutting bolt provided in an embodiment of the present application.

[0040] Figure 13 It is a schematic view of another structure of a cutting bolt provided in an embodiment of the present application.

[0041] Figure 14 It is a front view of a rotary cutting type fixed torque bolt provided in an embodiment of the present application; for the convenience of distinction, the end of the rotary cutting head is coated in gray. Figure 13 It is a sectional view of the cutting cap shown in FIG. 5.

[0042] Figure 15 It is a schematic view of another structure of a rotary cutting type fixed torque bolt provided in an embodiment of the present application.

[0043] Figure 16 It is a front view of a rotary cutting type fixed torque bolt provided in an embodiment of the present application; for the convenience of distinction, the end of the rotary cutting head is coated in gray. Figure 15 It is a top view of the rotary cutting type fixed torque bolt shown in FIG. 7.

[0044] Figure 17 It is a front view of a rotary cutting type fixed torque bolt provided in an embodiment of the present application; for the convenience of distinction, the end of the rotary cutting head is coated in gray. Figure 16 It is a sectional view at C-C in FIG. 7.

[0045] Figure 18 It is a schematic view of another structure of a rotary cutting type fixed torque bolt provided in an embodiment of the present application.

[0046] Figure 19 It is a front view of a rotary cutting type fixed torque bolt provided in an embodiment of the present application; for the convenience of distinction, the end of the rotary cutting head is coated in gray. Figure 18 It is a sectional view of the rotary cutting type fixed torque bolt shown in FIG. 9.

[0047] Marked description in the figure: cutting bolt 1, screw rod 11, external thread 111, head 12, wrenching structure 121, convex column 13, recess 14, rotary cutting head 15, pressure applying surface 151, notch 152, first annular clamping groove 16; cutting cap 2, cap body 21, light hole 22, second annular clamping groove 23, annular mounting groove 24, shielding part 25, vulnerable arm 26, pressure bearing surface 27, vulnerable groove 28, insertion hole 29; stop ring 3, ring body 31, fracture 32, first elastic clamping part 33, second elastic clamping part 34; mark 4. DETAILED DESCRIPTION

[0048] Embodiment 1

[0049] This embodiment provides a rotary cutting type constant torque bolt, including a cutting bolt 1, a retaining ring 3 and a cutting cover 2, wherein the cutting bolt 1 includes a bolt body and a protruding column 13 provided on the bolt body. The bolt body can adopt an existing bolt, such as Figure 1 As shown, the bolt body includes a head 12 and a screw 11 connected to one end of the head 12, the screw 11 is configured with an external thread 111, the head 12 is coaxial with the screw 11, and the outer side of the head 12 is configured with a wrench structure, which can include six planes configured on the outer side of the head 12, and the six planes form a hexagonal structure, as shown in FIG. Figure 1 As shown, it is suitable for common tightening tools such as wrenches, electric wrenches, etc.

[0050] like Figure 1 and Figure 2 As shown, the other end of the head 12 is connected to the boss 13, and the boss 13 is configured to fit the cut-off cover 2. In implementation, the outer side of the boss 13 is preferably configured as a cylinder, so that the entire boss 13 forms a cylinder, as shown in FIG. Figure 1 and Figure 2 As shown, the cutting cover 2 is more stably mounted and facilitates more stable rotation of the cutting cover 2 relative to the boss 13. In practice, the boss 13 is coaxial with the head 12 and the screw 11. The outer diameter of the boss 13 can be preferably equal to the outer diameter of the screw 11. Of course, in other embodiments, the outer diameter of the boss 13 can also be smaller or larger than the outer diameter of the screw 11. In addition, in practice, the boss 13 can also be constructed in the shape of a square column or other cylindrical-like structure, which will not be illustrated here one by one.

[0051] like Figure 1 and Figure 12 As shown in the figure, in this embodiment, a mark 4 is further provided on the end of the boss 13 away from the head 12, and at least two outwardly protruding (outwardly protruding along the axis of the boss 13) peeling heads 15 are provided along the circumference of the mark 4. Each peeling head 15 forms a circle and surrounds the mark 4 on the inside. In practice, the mark 4 is preferably provided at the center of the end of the boss 13, as shown in FIG. Figure 1 and Figure 12 As shown, each peeling head 15 can be evenly arranged along the circumferential direction of the central axis of the boss 13. In practice, the outer surface of the peeling head 15 is preferably flush with the outer side surface of the boss 13, as shown in FIG. Figure 1 and Figure 12As shown, this not only simplifies the structure but also facilitates integrated molding. In practice, the marking 4 can be a color marking 4. For example, a pigment (e.g., paint) can be printed or applied directly on the end face of the boss 13, between each rotary cutting head 15, to form the marking 4, achieving a marking effect. During later inspection, when the inspector sees the red paint on the bolt, they know that the bolt has been tightened and has reached the required preload value. This effectively simplifies the procedure for inspecting the bolt's tightening condition and significantly improves inspection efficiency. Furthermore, in practice, the marking 4 can also be an identification member provided on the end face of the boss 13. In practice, the identification member can be directly affixed to the end face of the boss 13, achieving a more eye-catching identification effect. During later inspection, when the inspector sees the identification member on the bolt, they know that the bolt has been tightened and has reached the required preload value, which is very simple and convenient. In practice, the identification member can preferably be a circular structure, which not only achieves a more eye-catching identification purpose but also has a more aesthetically pleasing appearance. Of course, in practice, the identification member can also be a truncated cone structure or a square structure. During implementation, the identification pieces are made of materials such as plastic or rubber, which can effectively reduce costs.

[0052] In a further embodiment, a groove 14 is further configured at the center of the end of the boss 13. Figure 2 As shown, at this time, the mark 4 can be set in the groove 14, which is not only more convenient to set the mark 4, but also helps the mark 4 to be more secure and helps prevent the mark 4 from falling off. During implementation, the shear bolt 1 is formed by forging or casting technology, so that the entire shear bolt 1 is an integrally formed component.

[0053] like Figures 3-5 As shown, in this embodiment, the cutting cover 2 includes a cover body 21 and a shielding portion 25. A light hole 22 is formed in the cover body 21. The light hole 22 does not have an internal thread. The light hole 22 extends through at least one end of the cover body 21 and is configured to fit over the protruding column 13. In practice, the light hole 22 in the cover body 21 can preferably be configured as a circular hole (i.e., the cross-section of the light hole 22 is circular). The outer diameter of the protruding column 13 is smaller than the inner diameter of the light hole 22. This allows the cutting cover 2 to be mounted on the protruding column 13 through the light hole 22. Furthermore, during use, the cutting cover 2 mounted on the protruding column 13 can rotate relative to the protruding column 13. It is understood that in practice, the light hole 22 in the cover body 21 can also be configured as a square hole, a special-shaped hole, or the like, as long as the cutting cover 2 can be mounted on the protruding column 13 and can rotate relative to the protruding column 13.

[0054] like Figure 3 、 Figure 4 、 Figure 13 and Figure 14As shown, in the present embodiment, the shielding portion 25 is arranged at a position corresponding to the center of the light hole 22, so as to shield the mark 4 at the end of the convex column 13 by means of the shielding portion 25; in implementation, the shape of the shielding portion 25 is adapted to the shape of the mark 4, and the area of the shielding portion 25 is greater than or equal to the area of the mark 4; for example, as shown in Figure 3 or Figure 13 As shown, the shielding portion 25 is configured as a circular structure, and the diameter of the shielding portion 25 is equal to the diameter of the mark 4, which not only facilitates the molding, but also can completely cover and shield the mark 4 before the pre-tightening force is reached. In implementation, the size of the shielding portion 25 is configured to be smaller than the size of the light hole 22, and the edges of the shielding portion 25 are connected to the cover body 21 by means of at least two frangible arms 26, which not only can stably support the shielding portion 25 by means of the frangible arms 26, but also can form an insertion hole 29 between the adjacent two frangible arms 26 for the insertion of the rotary cutting head 15, as shown in Figure 3 、 Figure 4 and Figure 13 As shown, the insertion hole 29 is actually surrounded by the adjacent two frangible arms 26, the outer side wall of the shielding portion 25, and the inner side wall of the cover body 21, and in implementation, the size of the insertion hole 29 is greater than or equal to the size of the rotary cutting head 15, and the number of the rotary cutting heads 15 is equal to the number of the insertion holes 29, for example, the number of the rotary cutting heads 15 can be preferably 2, 3, 4, 5, 6, etc.; so that in assembly, the rotary cutting head 15 corresponds to the insertion hole 29. As an example, the light hole 22 is a circular hole, the shielding portion 25 is configured as a circular structure, the frangible arm 26 is a columnar structure, and the frangible arm 26 is arranged along the radial direction of the cover body 21, so that a plurality of arc-shaped insertion holes 29 can be formed along the circumferential direction of the shielding portion 25, as shown in Figure 13 and Figure 14 As shown, correspondingly, the rotary cutting head 15 can be configured to adapt to the arc-shaped structure of the insertion hole 29, as shown in Figure 1 and Figure 12 In one embodiment, with the center of the convex column 13 as the center, the central angle corresponding to the rotary cutting head 15 can be equal to the central angle corresponding to the insertion hole 29, so that after the rotary cutting head 15 is inserted into the corresponding insertion hole 29, the cutting-off cover 2 cannot rotate relative to the convex column 13 before the frangible arm 26 is cut off or crushed. In another embodiment, with the center of the convex column 13 as the center, the central angle corresponding to the rotary cutting head 15 can be greater than the central angle corresponding to the insertion hole 29, as shown in Figure 8 , which not only facilitates the insertion of the rotary cutting head 15 into the corresponding insertion hole 29, achieving faster and more efficient assembly, but also provides the cutting-off cover 2 with a certain degree of freedom of rotation relative to the convex column 13 before the frangible arm 26 is cut off or crushed.

[0055] In actual production, the shielding part 25 has multiple setting positions, and the shielding part 25 can be arranged in the light hole 22. For example, in some embodiments, the light hole 22 penetrates through both ends of the cover body 21, the shielding part 25 is arranged in the light hole 22, and the shielding part 25 is connected to the inner side wall of the light hole 22 through at least two frangible arms 26. In implementation, the shielding part 25 can also be arranged at one end of the light hole 22 and does not protrude outward from the cover body 21. For example, in some embodiments, the light hole 22 only penetrates through one end of the cover body 21, at least two insertion holes 29 are formed at one end of the cover body 21, each insertion hole 29 is in communication with the light hole 22, and each insertion hole 29 is distributed along the circumferential direction of the central axis of the light hole 22, so that the frangible arm 26 can be formed between two adjacent insertion holes 29, and the shielding part 25 can be formed at the middle position of each insertion hole 29. As shown in Figure 3 and Figure 4 the shielding part 25 is coaxial with the light hole 22. In this embodiment, the shielding part 25 and the frangible arm 26 can be quickly formed by machining the insertion hole 29, which is not only convenient for machining and manufacturing, but also facilitates the entire cut-off cover 2 to be smaller and more convenient for subsequent inspection of the mark 4. In implementation, the shielding part 25 can also be arranged outside the end of the cover body 21. For example, in some embodiments, the light hole 22 penetrates through both ends of the cover body 21, the shielding part 25 and the frangible arm 26 are arranged outside the end of the cover body 21, the frangible arm 26 is connected to the end of the cover body 21, and the shielding part 25 corresponds to the center of the light hole 22. Each insertion hole 29 is in communication with the light hole 22 and can cooperate with the cut-off bolt 1. Here, the embodiments are not described one by one.

[0056] In order to facilitate the application of tightening force to the cut-off bolt 1 through the cut-off cover 2, in implementation, the outer side of the cover body 21 is also provided with a wrenching structure 121. The wrenching structure 121 can include six planes formed on the outer side wall of the cover body 21 to form a hexagonal structure, as shown in Figure 3 and Figure 13 so as to adapt to common wrenching tools such as wrenches, electric wrenches, etc. In addition, in implementation, the wrenching structure 121 can also include four planes formed on the outer side wall of the cover body 21 to form a square structure, and the wrenching structure 121 can also include a twelve-sided structure formed on the outer side wall of the cover body 21 to adapt to a socket wrench. It can be understood that the wrenching structure 121 has multiple embodiments, which are not described one by one here.

[0057] In this embodiment, the main function of the retainer ring 3 is to prevent the cut-off cover 2 from moving axially along the protruding column 13 and falling off, and the retainer ring 3 does not limit the freedom of rotation of the cut-off cover 2 relative to the protruding column 13, so that the cut-off cover 2 can rotate relative to the protruding column 13 after being sleeved on the protruding column 13, but cannot move axially relative to the protruding column 13.

[0058] For the convenience of setting the retainer ring 3, in the implementation, the outer side of the protruding column 13 is configured with a first annular clamping groove 16, as shown in Figure 1 or Figure 12 Accordingly, the inner side wall of the cover 21 (i.e. the inner side wall of the light hole 22) is configured with a second annular clamping groove 23, as shown in Figure 5 and Figure 14 When assembled, the cutting cover 2 is sleeved on the protruding column 13 through the light hole 22, the rotary cutting head 15 is inserted into the insertion hole 29, the blocking part 25 just blocks the mark 4 at the end of the protruding column 13, and the cutting cover 2 is coaxial with the protruding column 13. At this time, the retainer ring 3 is set between the protruding column 13 and the cutting cover 2, the retainer ring 3 is clamped at the first annular clamping groove 16, so that the retainer ring 3 is limited and constrained in the first annular clamping groove 16, and the retainer ring 3 is not easy to fall off from the protruding column 13. At the same time, the retainer ring 3 is also clamped at the second annular clamping groove 23, so that the cutting cover 2 is limited and constrained by the second annular clamping groove 23 to the retainer ring 3, and the cutting cover 2 is not easy to move along the axial direction of the protruding column 13, so that the cutting cover 2 is not easy to fall off from the protruding column 13. At the same time, the cutting cover 2 can rotate relative to the retainer ring 3 and / or the protruding column 13 to meet the action requirement of cutting the vulnerable arm 26. In the implementation, the retainer ring 3 has various embodiments, for example, the retainer ring 3 can adopt existing hole retainer rings or C-shaped retainer rings, etc. In actual application, the existing retainer ring 3 is not easy to assemble, the cutting cover 2 is easy to fall off, and the frictional resistance of the cutting cover 2 is larger, so that the cutting cover 2 needs to overcome a larger frictional resistance to reach the required pre-tightening force value, which has the problem of not saving labor. Therefore, in another embodiment, as shown in Figure 6 and Figure 7 The retainer ring 3 includes a ring body 31 and a second elastic clamping part 34 adapted to the second annular clamping groove 23, the second elastic clamping part 34 is arranged on the ring body 31 and protrudes outward from the outer surface of the ring body 31; in the implementation, the cross-sectional shape of the ring body 31 is preferably rectangular, as shown in Figure 6 and Figure 7 Not only is it beneficial to make the overall structure more compact, but it is also beneficial to prevent falling off and achieve better anti-falling effect. In the implementation, the ring body 31 can be configured with one or more second elastic clamping parts 34, and in the preferred embodiment, a plurality of second elastic clamping parts 34 are arranged along the circumferential direction of the ring body 31. The number of second elastic clamping parts 34 can be preferably controlled to be 3-6, for example, in the present embodiment, the number of second elastic clamping parts 34 is 4, and the 4 second elastic clamping parts 34 are evenly distributed along the circumferential direction of the ring body 31, as shown in Figure 6 At the same time, the side wall of the ring body 31 is configured with a fracture 32, as shown in Figure 6As shown, the inner diameter of the ring body 31 is smaller than the outer diameter of the convex column 13, the width of the first annular clamping groove 16 is greater than or equal to the width of the ring body 31, and the ring body 31 has a certain elasticity, so that the ring body 31 can be sleeved on the outer side of the convex column 13, and the ring body 31 is limited and constrained in the first annular clamping groove 16, as shown in Figures 8-10 As shown, not only the purpose of sleeving the retainer ring 3 on the outer side of the convex column 13 and limiting and constraining it in the first annular clamping groove 16 is achieved, but also the retainer ring 3 is not easy to fall off from the convex column 13; and the frictional resistance of the cutting cover 2 can be reduced, so that the tightening process of the bolt is more labor-saving.

[0059] As shown Figure 6 and Figure 7 In this embodiment, the second elastic clamping part 34 adopts a sheet-shaped elastic sheet, which has a certain elasticity. In implementation, the elastic sheet can be welded to the ring body 31, but in this embodiment, the elastic sheet and the ring body 31 are an integral structure, so that the entire retainer ring 3 is an integrally formed member, as shown in Figure 6 and Figure 7 As an example, in implementation, the ring body 31 can be manufactured first, then the shape of the elastic sheet is cut on the side wall of the ring body 31 by cutting, and the upper end of the elastic sheet is kept connected with the ring body 31, then the entire elastic sheet is rotated outward relative to the upper end of the elastic sheet by extruding the elastic sheet outward, so that the lower end of the elastic sheet is gradually opened and forms an opening, so that the lower end of the elastic sheet protrudes out of the outer surface of the ring body 31, as shown in Figure 6 and Figure 7 Not only is it convenient for production and manufacturing, but also the elastic sheet has elasticity, so that the assembly work of the elastic sheet can be completed very simply and labor-savingly.

[0060] In assembly, the retainer ring 3 is first sleeved on the outer surface of the convex column 13, and then the retainer ring 3 is pushed towards the head 12, so that the retainer ring 3 is clamped into the first annular clamping groove 16, at this time, the distance between the second elastic clamping part 34 (elastic sheet) and the ring body 31 gradually decreases in the direction away from the head 12, as shown in Figure 10 that is, the second elastic clamping part 34 keeps the state of the opening downward; then the light hole 22 of the cutting cover 2 is aligned with the convex column 13, and the cutting cover 2 is gradually moved close to and covers the convex column 13, so that the convex column 13 can be smoothly inserted into the light hole 22, and the rotating cutting heads 15 can be aligned with the insertion holes 29 during movement, so that the rotating cutting heads 15 are gradually inserted into the insertion holes 29, in this process, the lower end of the cutting cover 2 gradually contacts and extrudes the second elastic clamping part 34 (elastic sheet) inward, so that the second elastic clamping part 34 is elastically deformed inward, when the cutting cover 2 is installed in place, the second elastic clamping part 34 is clamped into the second annular clamping groove 23 automatically under the action of its own elasticity, as shown in Figure 10As shown, thereby clamping the cutting-off cover 2, effectively preventing the cutting-off cover 2 from moving along the axial direction of the protruding column 13 and falling off. In addition, since the second annular clamping groove 23 is annularly structured, and the second elastic clamping part 34 is clamped in the second annular clamping groove 23, the cutting-off cover 2 can rotate relative to the protruding column 13 under the action of external force without considering the blocking of the vulnerable arm 26, thereby effectively meeting the action requirement of cutting off the vulnerable arm 26.

[0061] In use, the specific process of using the present rotary cutting type torque limiting bolt to achieve torque limiting bolt connection is as follows: first, the screw rod 11 in the cutting-off bolt 1 is inserted through the through hole on the connected component (such as a plate), then the nut matched with the screw rod 11 is threadedly connected to the screw rod 11, so that the connected component is clamped between the nut and the head 12 of the cutting-off bolt 1, then the wrenching tool (such as a wrench) is used to clamp the wrenching structure 121 on the side of the cutting-off cover 2, the wrenching tool drives the cutting-off cover 2 to rotate through the wrenching structure 121, the vulnerable arm 26 of the cutting-off cover 2 contacts and presses the corresponding rotary cutting head 15 to transmit the torque, so that the whole cutting-off bolt 1 and the cutting-off cover 2 are driven to rotate synchronously through the cooperation of the vulnerable arm 26 and the rotary cutting head 15, so that the distance between the nut and the head 12 gradually decreases, thereby gradually clamping the connected component; in the process of rotation, the pressing force between the vulnerable arm 26 and the rotary cutting head 15 gradually increases, when the pressing force on the vulnerable arm 26 reaches the limit, the vulnerable arm 26 will be cut off or broken by the rotary cutting head 15, at this time, on the one hand, the pre-tightening force between the screw rod 11 and the nut reaches the required pre-tightening force value (or the required pre-tightening force value or the set torque value), on the other hand, the cutting-off cover 2 can continue to rotate relative to the cutting-off bolt 1, and the shielding part 25 can smoothly fall off from the cutting-off cover 2, so that the exposed mark 4 is exposed, such as Figure 11 As shown, playing a role of identification, indicating that the rotary cutting type torque limiting bolt has been tightened, when the inspection personnel inspect the fastening condition of the bolt, the prominent mark 4 in the bolt connection can be used to judge that the bolt has been tightened according to the requirements, not only can the drawbacks in the bolt inspection in the prior art be avoided, but also the bolt inspection process is very simple, convenient, efficient and safe, and the situation of missed inspection is not easy to occur.

[0062] It can be understood that after the vulnerable arm 26 is cut off or broken by the rotary cutting head 15, the cutting-off cover 2 can rotate relative to the cutting-off bolt 1, and the cutting-off bolt 1 is no longer synchronously rotated with the cutting-off cover 2, therefore, even if the operator continues to wrench the wrenching tool, the cutting-off bolt 1 will not continue to rotate, so that the cutting-off bolt 1 can maintain the required (preset) pre-tightening force, and the situation of excessive pre-tightening force will not occur, achieving the effect of torque limiting.

[0063] Since, during actual use, the torque applied by the operator directly acts on the cutting cover 2, the cutting cover 2 applies an extrusion force to the rotary cutting head 15 through the consumable arm 26. When the consumable arm 26 is cut or crushed by the rotary cutting head 15, the cutting bolt 1 just reaches the required or preset preload value. Therefore, during production and manufacturing, different preload requirements can be achieved by controlling parameters such as the material or size parameters (such as thickness, width) or structural parameters (such as shape) of the consumable arm 26. Since there is no threaded connection between the cut-off cover 2 and the cut-off bolt 1, when the cut-off cover 2 does not rotate relative to the cut-off bolt 1, the torsional force borne by the cut-off cover 2 can directly act on each rotary cutting head 15 through the vulnerable arm 26. There is no need to consider the resistance change caused by the threaded connection during calculation, let alone the resistance change caused by the thread fit accuracy, which is conducive to a simpler and more accurate calculation process; in the process where the vulnerable arm 26 is cut off and the cut-off cover 2 rotates relative to the cut-off bolt 1, the friction force between the cut-off cover 2 and the boss 13 and the stop ring 3 is a basically unchanged fixed value, and there is no problem of resistance change caused by thread fit accuracy. The torsional force borne by the cut-off cover 2 overcomes the fixed friction force and then rotates relative to the cut-off bolt 1. Therefore, there is no need to consider the resistance change and uncertainty caused by the threaded connection during calculation, which is conducive to a simpler and more accurate design calculation process, which is very convenient for industrial mass production.

[0064] During implementation, the fragile arm 26 can be a cylindrical structure, a square column structure, or other special-shaped structures. For example, in this embodiment, the fragile arm 26 is a square column structure. Figure 3 As shown, it is convenient for forming and for calculating and controlling the preload value. In practice, the size and shape of the contact surface between the rotary cutting head 15 and the consumable arm 26 can be determined according to actual needs. For example, the side of the rotary cutting head 15 facing the consumable arm 26 can be constructed as a knife-edge structure to facilitate cutting the consumable arm 26. In practice, the consumable arm 26 that meets the preload requirements can be determined experimentally. For another example, the contact surface between the rotary cutting head 15 and the consumable arm 26 can be a plane, which makes it easier to design the consumable arm 26 that meets the preload requirements through calculation.

[0065] In some embodiments, the consumable arm 26 is further configured with a consumable portion. By configuring the consumable portion on the consumable arm 26, the strength and rigidity of the consumable arm 26 are reduced, so that the consumable arm 26 meets the required preload force requirements. In practice, the consumable portion can be a hole or a groove configured on the consumable arm 26. For example, Figure 13 As shown, a fragile groove 28 is configured on one side of the fragile arm 26. The size or depth of the fragile groove 28 is used to change the strength and rigidity of the fragile arm 26, so that the fragile arm 26 can meet different preload requirements.

[0066] It can be understood that, in implementation, the structural parameters and forms of the vulnerable arm 26 can be manufactured in accordance with standard bolt specifications and strength grades, so that various specifications of rotary cutting type torque limiting bolts can be manufactured to meet the needs of different occasions.

[0067] Embodiment 2

[0068] To solve the problem of more convenient, labor-saving and efficient installation of the retainer ring 3, the main difference between the present embodiment 2 and the above-mentioned embodiment 1 is that the structure of the retainer ring 3 in the rotary cutting type torque limiting bolt provided by the present embodiment is different. Specifically, as shown in Figures 15-17 , the retainer ring 3 includes a ring body 31, a first elastic clamping portion 33 arranged on the inner side of the ring body 31, and a second elastic clamping portion 34 arranged on the outer side of the ring body 31. The first elastic clamping portion 33 is concave to the inner surface of the ring body 31, and the second elastic clamping portion 34 is convex to the outer surface of the ring body 31. In implementation, a plurality of first elastic clamping portions 33 and a plurality of second elastic clamping portions 34 can be arranged along the circumferential direction of the ring body 31. In specific implementation, the ring body 31 can be provided with 3-6 first elastic clamping portions 33 and 3-6 second elastic clamping portions 34, and the first elastic clamping portions 33 and the second elastic clamping portions 34 are arranged alternately along the circumferential direction of the ring body 31, as shown in Figure 16 , not only conducive to achieving better clamping effect and effectively preventing falling off, but also conducive to more convenient and efficient installation of the retainer ring 3. In addition, the friction between the retainer ring 3 and the protruding column 13 and the friction between the retainer ring 3 and the cutting cover 2 are greatly reduced, so that the frictional resistance of the cutting cover 2 is smaller, and the tightening process is more labor-saving. As an example, as shown in Figure 16 , the ring body 31 is provided with 3 first elastic clamping portions 33 and 3 second elastic clamping portions 34, and the 3 first elastic clamping portions 33 are uniformly distributed along the circumferential direction of the ring body 31, and at the same time, the 3 second elastic clamping portions 34 are also uniformly distributed along the circumferential direction of the ring body 31, as shown in Figure 15 and Figure 16 . In implementation, the first elastic clamping portion 33 and the second elastic clamping portion 34 both adopt a sheet-shaped elastic sheet, which has a certain elasticity. In implementation, the elastic sheet can be welded to the ring body 31, but in the present embodiment, the elastic sheet and the ring body 31 are of an integral structure, so that the entire retainer ring 3 is an integrally formed member, as shown in Figure 15 . As an example, in implementation, the ring body 31 can be manufactured first, and then the shape of the elastic sheet is cut on the side wall of the ring body 31 by cutting, keeping one part of the upper end of the elastic sheet connected to the ring body 31 and the other part of the lower end of the elastic sheet connected to the ring body 31. Then, by extruding the elastic sheet outward, the elastic sheet connected to the ring body 31 at the upper end is folded outward at a certain angle, and the lower end of the elastic sheet is gradually opened to form an opening, thereby forming the second elastic clamping portion 34, as shown in Figures 15-17Similarly, by squeezing the spring inward, the spring connected to the ring body 31 at the lower end is folded inward at a certain angle, so that the upper end of the spring gradually opens and forms an opening, thereby forming a first elastic holding portion 33, as shown Figures 15-17 As shown, the stop ring 3 has a two-way clamping function. It can be understood that in this embodiment, as Figure 15 As shown, the opening of the first elastic holding portion 33 in the retaining ring 3 is upward, that is, in the direction away from the head 12, the distance between the first elastic holding portion 33 and the ring body 31 gradually increases to prevent the retaining ring 3 from falling off from the boss 13; Figure 15 As shown, the opening of the second elastic holding portion 34 in the retaining ring 3 is downward, that is, along the direction away from the head 12, the distance between the second elastic holding portion 34 and the ring body 31 gradually decreases to prevent the cutting cover 2 from falling off the retaining ring 3.

[0069] Accordingly, in this embodiment, the inner side wall of the light hole 22 is further configured with an annular mounting groove 24, such as Figure 14 As shown, the lower end of the annular mounting groove 24 passes through the lower end of the cover body 21, and the second annular clamping groove 23 is constructed on the side wall of the annular mounting groove 24. The annular mounting groove 24 is mainly used to accommodate the ring body 31 of the backstop ring 3. Therefore, in implementation, the width of the annular mounting groove 24 is configured to be greater than or equal to the width of the ring body 31, and the depth of the annular mounting groove 24 is configured to be greater than or equal to the thickness of the ring body 31, so that the annular mounting groove 24 can accommodate the ring body 31 of the backstop ring 3, as shown in FIG. Figure 19 shown.

[0070] In practice, the inner diameter of the ring body 31 is greater than or equal to the outer diameter of the boss 13. For example, the inner diameter of the ring body 31 is greater than or equal to the inner diameter of the light hole 22, and the outer diameter of the ring body 31 is less than or equal to the inner diameter of the side wall of the annular mounting groove 24. This not only allows the ring body 31 of the retaining ring 3 to be smoothly installed in the annular mounting groove 24, but also allows the retaining ring 3 to be smoothly installed in the annular mounting groove 24. Figure 19 As shown, it is also helpful to sleeve the retaining ring 3 on the outer side of the boss 13 more simply and labor-savingly.

[0071] During implementation, the side wall of the ring body 31 can be easily assembled without constructing the fracture 32, so that the ring body 31 forms a complete ring structure. Of course, in some embodiments, the side wall of the ring body 31 can also construct the fracture 32, such as Figure 15 As shown, the installation of the retaining ring 3 will not be affected.

[0072] like Figure 18 and Figure 19As shown, during assembly, the ring body 31 of the stop ring 3 can be first aligned with the annular mounting groove 24 of the cutting cover 2, and the ring body 31 of the stop ring 3 can be gradually inserted into the annular mounting groove 24. When inserted into place, the second elastic clamping portion 34 on the outer side of the ring body 31 is automatically clamped into the second annular clamping groove 23, so that the stop ring 3 and the cutting cover 2 are connected as a whole, the cutting cover 2 can rotate relative to the stop ring 3, and the stop ring 3 and the cutting cover 2 are coaxial. Then align the lower end of the cutting cover 2 with the boss 13, move the cutting cover 2 in the direction close to the head 12, and the cutting cover 2 can be sleeved on the outside of the boss 13. When the cutting cover 2 is installed in place, the first elastic clamping portion 33 on the inner side of the ring body 31 is automatically clamped into the first annular clamping groove 16, so that the boss 13 and the stop ring 3 are connected as a whole, and the stop ring 3 can rotate relative to the boss 13, and the stop ring 3 is coaxial with the boss 13; at this time, the cutting cover 2 is firmly constrained to the boss 13 of the cutting bolt 1 through the stop ring 3, effectively preventing the cutting cover 2 from falling off, and the cutting cover 2 has the freedom to rotate relative to the boss 13.

[0073] Example 3

[0074] In order to solve the problem of more precise control of the pre-tightening force, the main difference between this embodiment 3 and the above embodiments is that, in the rotary-cut constant torque bolt provided in this embodiment, a pressure-bearing surface 27 is constructed on one side of the vulnerable arm 26, and correspondingly, a pressure-applying surface 151 adapted to the pressure-bearing surface 27 is constructed on one side of the rotary-cut head 15. After the rotary-cut constant torque bolt is assembled, the pressure-applying surface 151 of the rotary-cut head 15 corresponds to the pressure-bearing surface 27 of the vulnerable arm 26. During the tightening process, the pressure-applying surface 151 of the rotary-cut head 15 can contact the corresponding pressure-bearing surface 27, so that the cutting cover 2 can transmit the acting force through the contact between the pressure-bearing surface 27 and the pressure-applying surface 151, so as to drive the cutting bolt 1 to rotate; during implementation, the pressure-bearing surface 27 and the pressure-applying surface 151 are both constructed as planes, such as Figure 8 、 Figure 9 、 Figure 18 or Figure 19 As shown, force transmission between planes is achieved, which makes it easier to calculate the pressure on the fragile arm 26. This not only further simplifies the amount of calculation in the design stage, but also makes the calculation results more accurate and more in line with the actual situation, thereby achieving the purpose of more precise control of the preload force.

[0075] During implementation, the setting angles of the pressure-bearing surface 27 and the pressure-applying surface 151 can be determined according to actual needs. For example, the pressure-bearing surface 27 and the pressure-applying surface 151 can be arranged at a certain angle. In order to further simplify the calculation and improve the calculation accuracy, in a further embodiment, the pressure-bearing surface 27 is coplanar with the central axis of the cover body 21, such as Figure 4 and Figure 19As shown, i.e., the pressure receiving surface 27 is arranged along the radial direction of the cover body 21, so that the rotation direction of the pressure receiving surface 27 is perpendicular to the rotary cutting head 15; correspondingly, the pressure applying surface 151 is coplanar with the central axis of the convex column 13, as shown in Figure 1 or Figure 12 As shown, i.e., the pressure applying surface 151 is arranged along the radial direction of the convex column 13, when the pressure receiving surface 27 contacts and presses the pressure applying surface 151, the pressure received by the pressure receiving surface 27 is just perpendicular to the pressure receiving surface 27, forming a positive vertical pressure, which not only can further simplify the calculation, greatly reduce the calculation amount in the design stage, but also make the calculation result more accurate, so as to more conveniently and accurately control the structure and / or material of the vulnerable arm 26, so that the pre-tightening force between the cut-off bolt 1 and the nut just reaches the required pre-tightening force value when the vulnerable arm 26 is cut off or broken by the rotary cutting head 15, thereby achieving the purpose of more accurately controlling the pre-tightening force.

[0076] As shown in Figure 1 and Figure 12 In implementation, the end of the rotary cutting head 15 away from the pressure applying surface 151 is also configured with a notch 152, which not only makes it more convenient and efficient to insert the rotary cutting head 15 into the corresponding insertion hole 29 during assembly, but also makes the vulnerable arm 26 not easy to be clamped between two rotary cutting heads 15, so as to avoid interference with the rotary cutting head 15, thereby improving the reliability, in addition, during the tightening process, especially after the vulnerable arm 26 is cut off or broken by the rotary cutting head 15, the vulnerable arm 26 is more likely to fall through the notch 152. Figure 1 As shown, the notch 152 adopts an oblique cutout.

[0077] Embodiment 4

[0078] The embodiment provides a fastener, which comprises the above-mentioned rotary cutting type torque limiting bolt, and further comprises a nut matched with the screw rod 11, the nut is configured with an internal thread matched with the screw rod 11, the length of the external thread 111 is greater than or equal to the length of the internal thread, and the nut is threadedly connected to the screw rod 11.

[0079] In actual use, the screw rod 11 in the cut-off bolt 1 passes through the through hole on the connected component and is threadedly connected with the nut, the connected component is clamped between the nut and the head 12 of the cut-off bolt 1, then the cut-off cover 2 is rotated by a wrenching tool, so that the pre-tightening force between the cut-off bolt 1 and the nut reaches the required pre-tightening force value, and when the pre-tightening force between the cut-off bolt 1 and the nut reaches the required pre-tightening force value, the vulnerable arm 26 is just cut off or broken by the rotary cutting head 15, the shielding part 25 falls from the cut-off cover 2, and the mark 4 at the end of the convex column 13 is exposed, so that the inspection personnel can more conveniently and efficiently complete the inspection work.

[0080] It can be understood that when the bolt needs to be disassembled, the operator can loosen or disassemble the bolt by cutting off the wrenching structure on the bolt 1.

[0081] The above merely illustrates the present application, but the protection scope of the present application is not limited to this. Any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered by the protection scope of the present application.

Claims

1. A rotary cut constant torque bolt, characterized in that: The invention comprises a cutting bolt, a retaining ring and a cutting cover. The cutting bolt comprises a bolt body, the bolt body comprises a head and a screw connected to one end of the head, the screw having an external thread, the other end of the head having a boss, the end of the boss having a mark, and at least two outwardly protruding rotary cutting heads being provided along the circumference of the mark; the outer side surface of the boss is cylindrical, and the boss is coaxial with the screw; The cutting cover includes a cover body and a shielding portion. The outer side of the cover body is configured with a wrench structure. The cover body is configured with a light hole adapted to the boss. The light hole is configured as a circular hole. The outer diameter of the boss is smaller than the inner diameter of the cover body. The shielding portion is arranged at a position corresponding to the center of the light hole. The shielding portion is connected to the cover body through at least two fragile arms. A socket for inserting a rotary cutting head is formed between two adjacent fragile arms. The socket is configured as an arc-shaped structure. The rotary cutting head is configured as an arc-shaped structure adapted to the socket. The center of the circle is the center of the boss. The central angle corresponding to the rotary cutting head is greater than or equal to the central angle corresponding to the socket. A pressure-bearing surface is constructed on one side of the consumable arm, and a pressure-applying surface adapted to the pressure-bearing surface is constructed on one side of the rotary cutting head. Both the pressure-bearing surface and the pressure-applying surface are constructed as planes. The force is transmitted between the rotary cutting head and the consumable arm through the contact between the pressure-applying surface and the pressure-bearing surface. The outer side surface of the boss is configured with a first annular groove, and the inner side wall of the cover body is configured with a second annular groove; the cutting cover is sleeved on the boss, the rotary cutting head is inserted into the insertion hole, the shielding part shields the mark, and the stop ring is arranged between the boss and the cutting cover. The stop ring is limited and constrained by the first annular groove, and the cutting cover is limited and constrained by the stop ring through the second annular groove. The stop ring is used to prevent the cutting cover from falling off. The cutting cover contacts and squeezes the rotary cutting head through the consumable arm to transmit torque; at least after the consumable arm is cut off by the rotary cutting head, the cutting cover can rotate relative to the boss.

2. The rotary cut type constant torque bolt according to claim 1, characterized in that: The pressure-bearing surface is coplanar with the central axis of the cover body; the pressure-exerting surface is coplanar with the central axis of the convex column.

3. The rotary cut constant torque bolt according to claim 1, characterized in that: The wrench structure includes six planes constructed on the outer side wall of the cover body, and the six planes form a hexagonal structure; The consumable arm is configured with a consumable portion comprising a hole or a slot.

4. The rotary cut constant torque bolt according to any one of claims 1 to 3, characterized in that: The retaining ring includes a ring body and a second elastic retaining portion adapted to the second annular retaining groove, the second elastic retaining portion is provided on the ring body and protrudes outwardly from the outer surface of the ring body, and the second elastic retaining portion can be elastically deformed; The stop ring is sleeved on the outer side of the convex column and is limited and constrained in the first annular clamping groove. The cutting cover covers the stop ring, and the second elastic clamping part is clamped in the second annular clamping groove.

5. The rotary cut type constant torque bolt according to claim 4, characterized in that: A plurality of second elastic holding portions are provided along the circumferential direction of the ring body; the second elastic holding portions are spring sheets with a sheet structure; The number of the second elastic holding portions is 3-6; The retaining ring is an integrally formed component.

6. The rotary cut type constant torque bolt according to claim 4, characterized in that: The inner side wall of the light hole is further configured with an annular mounting groove for accommodating the ring body, the lower end of the annular mounting groove passes through the lower end of the cover body, and the second annular clamping groove is configured on the side wall of the annular mounting groove; The stop ring further includes a first elastic clamping portion provided on the ring body, the first elastic clamping portion protruding from the inner surface of the ring body; in a direction away from the head, the distance between the first elastic clamping portion and the ring body gradually increases, and the distance between the second elastic clamping portion and the ring body gradually decreases; The ring body is arranged in the annular installation groove, the first elastic clamping portion is clamped in the first annular clamping groove, and the second elastic clamping portion is clamped in the second annular clamping groove.

7. The rotary cut constant torque bolt according to claim 6, characterized in that: A plurality of first elastic holding portions and a plurality of second elastic holding portions are provided along the circumferential direction of the ring body, and the first elastic holding portions and the second elastic holding portions are arranged alternately; The first elastic holding portion is a spring; The second elastic holding portion is a spring.

8. A fastener comprising a nut, characterized in that: It also includes the rotary-cut constant torque bolt according to any one of claims 1 to 7, wherein the nut is threadedly connected to the screw rod.

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