A bolt and fastening assembly

Abstract

The utility model relates to a kind of bolt and fastening assembly, it is related to bolt fastener technical field, including head and the screw rod connected to the one end of head, screw rod is constructed with outer thread, it is characterized in that, the other end of head is constructed with cylinder, the end of cylinder is provided with mark and at least two outward convex spin cut head, each spin cut head is evenly arranged along the circumferential direction of cylinder respectively, and mark is enclosed in inside, there is gap between adjacent two spin cut heads;The outside of cylinder is constructed with a ring of first limiting slot, and the first limiting slot is located between spin cut head and head;The bolt of the utility model, not only more labor-saving during fastening process, but also more convenient for production and manufacturing, and cost is lower, very convenient for mass production and promotion.

Description

Technical Field

[0001] This utility model relates to the field of bolt fastener technology, specifically to a bolt and fastening assembly. Background Technology

[0002] A bolt is a mechanical part consisting of a head and a threaded shank. The external thread on the shank engages with the internal thread of the nut to achieve a bolted connection, thus securing two or more parts. The basic principle is that tightening the nut creates an axial preload on the bolt, clamping the connected parts together. Loads (such as tensile or shear forces) are transferred through friction or deformation of the bolt and the connected parts. Bolted connections are a common type of detachable connection, widely used in machinery manufacturing, construction engineering, the automotive industry, aerospace, and everyday consumer goods.

[0003] In bolted connections, bolt preload is a crucial technical indicator. Chinese patents CN 207961214U, CN209115491U, and CN207795801U all describe a bolt that ensures the required preload while facilitating quick and efficient inspection. This bolt includes a threaded rod, a head connected to the threaded rod, and a second threaded rod connected to the head. The second threaded rod has external threads, and its end has a relatively sharp protrusion with a mark on its end face. This mark primarily indicates that the bolt has been tightened. This bolt is mainly used with a torque-controlled nut (or torque-controlled nut). The torque nut is used in conjunction with a second screw. It has a threaded hole adapted to the second screw and a vulnerable part located at one end of the threaded hole. During product manufacturing, the parameters of the vulnerable part are related to the required preload. In use, the torque nut is threaded onto the second screw of the bolt, with the protrusion abutting against the vulnerable part, which covers the markings. Rotating the torque nut with a tool (such as a wrench) causes the torque nut and bolt to rotate synchronously. When the vulnerable part is broken by the end of the screw, the bolt connection reaches the required preload value, at which point the markings are exposed for subsequent inspection.

[0004] Because the torque-controlled nut is threaded onto the second thread of the bolt, the tightening process requires overcoming the frictional resistance between the nut and the bolt to transfer the lifting force to the vulnerable parts. The greater the torque, the greater the frictional resistance, making the tightening process more strenuous, especially when tightening manually. Furthermore, the machining accuracy of the thread directly affects the frictional resistance between the nut and the bolt. Therefore, precise control of the thread machining accuracy is necessary to ensure that the frictional resistance of different bolts is essentially the same, ultimately achieving precise control of the preload. However, higher thread machining accuracy increases cost, making mass production of this type of bolt difficult and requiring immediate attention. Summary of the Invention

[0005] The first aspect of this utility model is to solve the above-mentioned technical problems by providing a bolt that can be used with a constant torque cap, which not only makes the tightening process less labor-intensive, but also makes it easier to produce and manufacture, and has a lower cost, making it very convenient for mass production and promotion.

[0006] A bolt includes a head and a screw connected to one end of the head. The screw has an external thread. The other end of the head has a column. The end of the column is provided with a mark and at least two outwardly protruding cutting heads. Each cutting head is evenly arranged along the circumference of the column and surrounds the mark on its inner side. There is a gap between adjacent cutting heads. The outer surface of the column is provided with a first annular limiting groove located between the cutting head and the head. In this design, a column is constructed at the head, and a first annular limiting groove is formed on the outer surface of the column. A limiting ring is installed using this groove, allowing the torque cap to connect to the column via the limiting ring without the need for a threaded connection. Firstly, during bolt tightening, the frictional resistance between the torque cap and the bolt is significantly reduced, and this frictional resistance is a relatively constant value that does not increase with the torque during tightening. This not only makes the tightening process less strenuous but also facilitates more accurate calculations and designs during the design phase, achieving precise control of the preload. Secondly, it effectively avoids the high costs associated with machining high-precision threads, significantly reducing the cost of bolts with torque-controlled functionality and making production and manufacturing easier, thus facilitating mass production and widespread adoption. At least two outwardly protruding rotary cutting heads are provided at the end of the column, each evenly arranged along the circumference of the column with a gap between adjacent heads, ensuring that each cutting head operates independently. This design allows for precise insertion into the respective holes of the torque-controlled cap during assembly. This not only facilitates assembly but also ensures that during tightening, the torque-controlled cap rotates the bolt, contacting one side of the rotary cutter head and transmitting force to the bolt. When the bolt connection reaches the designed preload, the connecting post in the torque-controlled cap that contacts the rotary cutter head is crushed by the head, allowing the cap to rotate relative to the bolt and preventing further bolt rotation. This achieves precise control of the bolt connection preload, realizing the effect of a constant torque. Marks are placed on the inner side of each rotary cutter head. These marks are concealed by the torque-controlled cap during assembly, remaining hidden until the designed preload is reached. When the bolt connection reaches the designed preload, the marks are exposed, serving as an indicator that the bolt has reached the required preload value. Inspectors can visually check the marks to determine if the bolt has been tightened as required, making the inspection process more convenient and efficient.

[0007] Preferably, the column is constructed as a cylindrical structure, with the column and the screw coaxial. This simplifies the structure and effectively avoids uneven loading during tightening, making bolt design simpler and more efficient, and also facilitating precise control of the bolt preload.

[0008] Preferably, the outer diameter of the column is the same as the outer diameter of the screw. This simplifies the structure and makes production and manufacturing easier.

[0009] Furthermore, a groove is constructed at the center of the end of the column, and the mark is placed within the groove. This not only makes it easier to set the mark, but also helps the mark to be more stable and reliable.

[0010] Preferably, the number of rotary cutting heads is 2-5.

[0011] Preferably, one side of the rotary cutting head is provided with a contact surface, which is a plane and coplanar with the central axis of the column. By constructing a contact surface on one side of the rotary cutting head, the contact surface can be used to contact the connecting column in the constant torque cap. By making the contact surface a plane and coplanar with the central axis of the column, the force exerted by the constant torque cap on the rotary cutting head during tightening is perpendicular to the contact surface, i.e., a positive vertical pressure is formed. This not only further simplifies calculation and design, greatly reducing the amount of calculation in the design stage, but also makes the calculation results more accurate, thus making it easier to accurately control the preload of the bolt.

[0012] Preferably, the end of the rotary cutter head facing away from the contact surface is the back side, which is constructed as an inclined surface tilted in the vertical direction, with the inclined surface tilted towards the contact surface. During assembly, this facilitates faster and more efficient insertion of the rotary cutter head into the corresponding socket. Simultaneously, the connecting post of the torque cap is less likely to get stuck between the two rotary cutters, effectively preventing interference.

[0013] Preferably, the rotary cutting head has an arc-shaped structure. This facilitates low-cost implementation in the industry.

[0014] Preferably, the bolt is a one-piece molded component. This helps to ensure the reliability and stability of the bolted connection.

[0015] In some designs, the outer surface of the rotary cutting head is flush with the outer surface of the column. This not only further simplifies the structure but also facilitates the integral molding of bolts.

[0016] The second aspect of this utility model is to solve the problem of faster and more efficient assembly of the limiting ring. In some solutions, the column includes a first column segment and a second column segment connected coaxially. A mark and a rotary cutting head are respectively set at the end of the first column segment. The first column segment is constructed as a cylindrical structure. The outer diameter of the first column segment is smaller than the outer diameter of the second column segment. A positioning step is formed between the first column segment and the second column segment. The first limiting groove is constructed on the outer side of the first column segment. In this design, the column is constructed as a first column segment and a second column segment connected coaxially, with the outer diameter of the first column segment being smaller than that of the second column segment. A first limiting groove is constructed on the outer surface of the first column segment. On the one hand, during assembly, the limiting ring can be easily fitted onto the first column segment of the column. During the fitting process, the spring piece on the inner side of the limiting ring can automatically engage with the first limiting groove, thereby enabling faster and more efficient assembly of the limiting ring. On the other hand, since a positioning step is formed between the first column segment and the second column segment, the positioning step can limit and constrain the lower end of the limiting ring, preventing the limiting ring from continuing to move towards the head, making the assembly position of the limiting ring more stable, and thus facilitating the assembly of the torque cap.

[0017] Preferably, the outer surface of the head has a force-bearing portion to facilitate bolt removal by rotating the entire bolt with a fastening tool.

[0018] Preferably, the force-bearing portion includes six planes formed on the outer wall of the cover, the six planes forming a hexagonal structure to accommodate common fastening tools.

[0019] Preferably, the marking is a color mark or identifier to serve as a prominent identification feature.

[0020] A fastening assembly includes a nut and a bolt, the nut being threaded onto a bolt.

[0021] Compared with the prior art, the bolt and fastening assembly provided by this utility model not only makes the fastening process less labor-intensive, but also makes it easier to produce and manufacture, and has a lower cost, thus making it very easy to mass-produce and promote. Attached Figure Description

[0022] To more clearly illustrate the technical solutions of the embodiments of this utility model, the accompanying drawings used in the embodiments will be briefly described below.

[0023] Figure 1 This is a three-dimensional structural diagram of a bolt provided in an embodiment of the present utility model.

[0024] Figure 2 for Figure 1 The main view.

[0025] Figure 3 for Figure 2 Top view.

[0026] Figure 4 This is a partial three-dimensional structural diagram of another bolt provided in an embodiment of this utility model.

[0027] Figure 5 for Figure 4 Top view.

[0028] Figure 6 This is a three-dimensional structural diagram of a limiting ring provided in an embodiment of the present utility model.

[0029] Figure 7 This is a three-dimensional structural diagram of a constant torque cap provided in an embodiment of this utility model.

[0030] Figure 8 This is a partial three-dimensional structural diagram of a fastening component provided in Embodiment 2 of this utility model.

[0031] Figure 9 This is a front view of a fastening assembly provided in Embodiment 2 of this utility model.

[0032] Figure 10 This is a front view of a bolt provided in Embodiment 3 of this utility model.

[0033] Figure 11 This is a partial cross-sectional view of a fastening assembly provided in Embodiment 4 of this utility model.

[0034] Explanation of markings in the diagram: Bolt 1; Head 2, Force-bearing part 21; Screw 3, External thread 31; Column 4, Groove 41, Mark 42, Rotary cutting head 43, Contact surface 44, Back side 45, Gap 46, First limiting groove 47, First column segment 48, Second column segment 49, Positioning step 491; Limiting ring 5, Ring body 5 1. Spring piece 52; Torque cap 6; Inner hole 61; Covering piece 62; Connecting post 63; Insertion hole 64; Second limiting groove 65. Detailed Implementation

[0035] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0036] Example 1

[0037] like Figures 1-3 As shown, this embodiment provides a bolt 1, including a head 2, a screw 3 connected to one end of the head 2, and a post 4 connected to the other end of the head 2. The screw 3 is configured with external threads 31 for threaded connection to a nut. The end of the post 4 is provided with a mark 42 and at least two outwardly protruding cutting heads 43, such as... Figure 1 As shown, each rotary cutting head 43 is evenly arranged along the circumference of the column 4, and the mark 42 is surrounded on the inner side. There is a gap 46 between two adjacent rotary cutting heads 43, as shown. Figure 1 and Figure 3 As shown.

[0038] like Figure 1 and Figure 2 As shown, in implementation, the screw 3 is coaxial with the head 2. The outer surface of the head 2 has a force-bearing part 21. The force-bearing part 21 may include six planes constructed on the outer surface of the head 2, and the six planes form a hexagonal structure, such as... Figures 1-3 As shown, this is to accommodate common fastening tools, such as wrenches and electric wrenches. In implementation, the force-applying part 21 may also include four planes constructed on the outer side of the head 2, the four planes forming a square structure; the force-applying part 21 may also include a dodecagonal structure constructed on the outer side of the head 2 to accommodate a sleeve wrench; it is understood that the force-applying part 21 has multiple implementations, which will not be described one by one here.

[0039] like Figures 1-3 As shown, in implementation, the column 4 is preferably constructed as a cylindrical structure, and the column 4 is coaxial with the screw 3. Of course, in implementation, the column 4 can also be constructed as a square column or other similar cylindrical structure. The outer diameter of the column 4 can be determined according to actual needs; in implementation, the outer diameter of the column 4 can be smaller than or larger than the outer diameter of the screw 3. For example, ... Figure 2 As shown, the outer diameter of the column 4 is equal to the outer diameter of the screw 3, which not only facilitates integral molding, but also ensures the strength and rigidity of the column 4, so that the column 4 can drive the entire bolt 1 to rotate.

[0040] In implementation, the ends of the column 4 can be constructed to be planar, and the mark 42 can be set at the corresponding center position of the column 4. In a further embodiment, such as Figure 1 and Figure 3 As shown, a groove 41 is constructed at the center of the end of the column 4, and each rotary cutting head 43 is evenly arranged along the circumference of the groove 41. At this time, the mark 42 can be set in the groove 41, which not only makes it easier to set the mark 42, but also makes the mark 42 more secure and prevents the mark 42 from falling off.

[0041] In implementation, mark 42 can be a color mark. For example, pigment (such as paint) can be printed or applied directly to the end face of the column 4 to form mark 42, achieving the effect of identification. During inspection, when inspectors see the red paint on bolt 1, they know that bolt 1 has been tightened and reached the required preload value, thus effectively simplifying the inspection process and significantly improving inspection efficiency. In implementation, mark 42 can also be an identification piece set on the end face of the column 4. The identification piece can be directly pasted onto the column 4, for example, pasted into the groove 41, thus achieving a more conspicuous identification effect. During later inspection, when inspectors see the identification piece on bolt 1, they know that bolt 1 has been tightened and reached the required preload value, which is very simple and convenient. In implementation, groove 41 can preferably be a circular groove, such as... Figure 1 and Figure 3 As shown, circular signs are preferred, as they are not only more eye-catching but also more aesthetically pleasing. Of course, square or star-shaped signs can also be used, but these will not be listed here.

[0042] During implementation, the rotary cutting head 43 protrudes outward along the axial direction of the column 4, such as... Figures 1-5 As shown, the number of rotary cutting heads 43 can be determined according to actual needs. For example, in this embodiment, the bolt 1 can preferably be equipped with 2-5 rotary cutting heads 43. Figures 1-3 As shown, the end of the column 4 is provided with two rotary cutting heads 43, which are arranged opposite to each other; as another example, such as Figures 4-5 As shown, three rotary cutting heads 43 are provided at the end of the column 4, and the three rotary cutting heads 43 are evenly arranged along the circumference of the column 4. Of course, six rotary cutting heads 43, seven rotary cutting heads 43, etc. can also be configured, but they will not be listed here.

[0043] In implementation, one side of the rotary cutting head 43 is constructed with a contact surface 44 for contacting and pressing the constant torque cap 66. The size and shape of the contact surface 44 can be determined according to actual needs. For example, one side of the entire rotary cutting head 43 can be constructed as a knife-edge structure, so that the contact surface 44 can be an arc surface; however, in the preferred embodiment provided in this example, the contact surface 44 can preferably be a plane, such as... Figure 1 and Figure 4 As shown.

[0044] In practice, the contact surface 44 can be arranged at a certain angle; and for ease of design, production, and manufacturing, the contact surface 44 can preferably be coplanar with the central axis of the column 4, such as... Figure 3 and Figure 5As shown, the contact surface 44 is arranged along the radial direction of the column 4, so that the rotation direction of the rotary cutting head 43 is exactly perpendicular to the contact surface 44, which is more conducive to the vertical compression of the constant torque cap 66. In actual use, the contact surface 44 is used to contact the connecting column 63 in the constant torque cap 66. During the tightening process, the force exerted by the constant torque cap 66 on the rotary cutting head 43 is exactly perpendicular to the contact surface 44, that is, a positive vertical pressure is formed. This not only further simplifies the calculation and design, greatly reduces the amount of calculation in the design stage, but also makes the calculation results more accurate, thus making it easier to accurately control the preload of the bolt 1.

[0045] In implementation, the shape of the rotary cutting head 43 can be determined according to actual needs. For example, the rotary cutting head 43 can preferably be constructed as an arc-shaped structure, such as... Figure 1 and Figure 4 As shown; in a further embodiment, the end of the rotary cutting head 43 facing away from the contact surface 44 is a back surface 45, which is constructed as an inclined surface in the vertical direction, as shown. Figures 1-5 As shown, the inclined surface is inclined toward the contact surface 44, which makes the gap 46 between two adjacent rotary cutting heads 43 larger. During assembly, it is not only easier to quickly and efficiently insert the rotary cutting head 43 into the corresponding insertion hole 64, but also prevents jamming, making the bolt 1 more reliable.

[0046] During implementation, the outer surface of the rotary cutting head 43 is preferably flush with the outer surface of the column 4, such as Figure 1 and Figure 4 As shown, the outer diameter of the rotary cutting head 43 can be equal to the outer diameter of the column 4, which not only further simplifies the structure but also makes it easier to integrally form the bolt 1. Of course, in practice, the outer diameter of the rotary cutting head 43 can also be smaller than the outer diameter of the column 4, that is, each rotary cutting head 43 can be respectively set in the end face of the column 4.

[0047] like Figure 1 and Figure 2 As shown, in this embodiment, a ring-shaped first limiting groove 47 is also constructed on the outer surface of the column 4. The first limiting groove 47 is located between the rotary cutting head 43 and the head 2. The first limiting groove 47 is mainly used to limit and constrain the limiting ring 5, so that the constant torque cap 66 can be limited and constrained to the column 4 by the limiting ring 5 without the need for a threaded connection, thereby effectively avoiding the disadvantages of using a threaded connection. In implementation, the depth and width of the first limiting groove 47 can be determined according to actual needs, as long as it is adapted to the limiting ring 5. In implementation, the first limiting groove 47 is preferably set near the head 2, such as... Figure 1 and Figure 2 As shown, the first limiting groove 47 is constructed at the lower end of the column 4, which helps to make the setting of the constant torque cap 66 more stable.

[0048] In a more refined implementation, the bolt 1 is preferably formed by forging or casting, so that the entire bolt 1 is a one-piece molded component, as shown in the figure, so as to achieve low-cost and rapid molding.

[0049] Example 2

[0050] This embodiment provides a fastening assembly, including the bolt 1 in embodiment 1, and a nut adapted to the screw 3. The nut is threadedly connected to the screw 3 of the bolt 1. In use, the connected part is clamped between the nut and the head 2 to achieve the purpose of fastening.

[0051] To achieve a constant torque, in a more refined embodiment, this fastening assembly further includes a limiting ring 5 for the adapter bolt 1 and a constant torque cap 66 for the adapter bolt 1. The limiting ring 5 can be an existing hole-mounted anti-reverse ring or a C-type anti-reverse ring, etc. The limiting ring 5 is assembled within the first limiting groove, and the constant torque cap 66 is constrained and limited by the limiting ring 5. In this embodiment, as shown... Figure 6 As shown, the limiting ring 5 includes a ring body 51, a plurality of spring pieces 52 disposed on the inner side of the ring body 51, and a plurality of spring pieces 52 disposed on the outer side of the ring body 51. The spring pieces 52 on the inner side and the spring pieces 52 on the outer side are evenly distributed along the circumference of the ring body 51.

[0052] like Figure 7 As shown, the constant torque cap 66 has an inner hole 61 that fits the cylinder 4. A baffle 62 is provided at one end of the inner hole 61. The baffle 62 is coaxial with the inner hole 61 and is connected to the constant torque cap 66 via at least two connecting posts 63. An insertion hole 64 for inserting the rotary cutting head 43 is formed between adjacent connecting posts 63. Each insertion hole 64 communicates with the inner hole 61. Figure 7 As shown.

[0053] like Figure 9 As shown, the inner hole 61 of the constant torque cap 66 has a second limiting groove 65 on its side wall. The inner hole 61 is a stepped hole, and the stepped hole is a ring body 51 that is adapted to the limiting ring 5.

[0054] During assembly, first, the limiting ring 5 is inserted into the inner hole 61 of the torque cap 66. During insertion, the spring piece 52 on the outer side of the limiting ring 5 automatically engages into the second limiting groove 65, thus connecting the limiting ring 5 and the torque cap 66. Then, the column 4 is inserted into the inner hole 61 of the torque cap 66. During insertion, the spring piece 52 on the inner side of the limiting ring 5 automatically engages into the first limiting groove 47, thus connecting the limiting ring 5 and the column 4, thereby connecting the torque cap 66 and the bolt 1. Figure 9 As shown; when installed in place, each rotary cutting head 43 is inserted into its corresponding socket 64, as shown. Figure 8 and Figure 9 As shown.

[0055] During implementation, the parameters of the connecting post 63 need to be accurately calculated and designed, and the connecting post 63 needs to be precisely manufactured according to the design results, so that when the connecting post 63 is crushed, the bolt connection can better achieve the required preload value. In use, the torque cap 66 is rotated using a tightening tool. The torque cap 66 contacts and presses against the contact surface 44 of the rotary cutting head 43 through the connecting post 63, as shown... Figure 8 As shown, the torque cap 66 rotates synchronously with the bolt 1, and the bolt 1 is gradually tightened. When the connecting post 63 is broken by the rotary cutter 43, the bolt connection reaches the required preload value. At this time, the shield 62 automatically falls off due to the breakage of the connecting post 63, so that the mark 42 at the end of the post 4 is exposed for subsequent inspection.

[0056] This fastening assembly simplifies the calculation and design process of bolted connections, enabling more precise control of the bolt preload and facilitating production and manufacturing, thus enabling mass production in industry. Furthermore, when the preload is reached, the connecting post 63 is broken by the cutting head 43, allowing the torque nut to rotate relative to the cut bolt 1, achieving a constant torque. Simultaneously, the shielding plate 62 detaches smoothly from the torque nut, exposing the mark 42 previously hidden by the shielding plate, serving as an identification marker for efficient subsequent inspection. Moreover, this fastening assembly achieves the required preload without the need for specialized tools, broadening its application range.

[0057] Example 3

[0058] To address the issue of assembling the limiting ring 5 onto the column 4 more quickly and efficiently, the main difference between this embodiment 3 and the aforementioned embodiment 1 is that the column 4 in the bolt 1 provided in this embodiment adopts a stepped structure. The number of steps can be determined according to actual needs. For example, in this embodiment, the column 4 includes a first column segment 48 and a second column segment 49 coaxially connected, such as... Figure 10 As shown, mark 42 and rotary cutting head 43 are respectively disposed at the ends of the first column segment 48. The first column segment 48 is constructed as a cylindrical structure, and the outer diameter of the first column segment 48 is smaller than the outer diameter of the second column segment 49, so that a positioning step 491 for positioning and limiting ring 5 is formed between the first column segment 48 and the second column segment 49. Figure 10 and Figure 11 As shown, at this time, the first limiting groove 47 is constructed on the outer side of the first column segment 48 so as to install the limiting ring 5 on the first column segment 48.

[0059] In implementation, the outer diameter of the first column segment 48 is smaller than the inner diameter of the limiting ring 5, allowing the first column segment 48 to be inserted into the limiting ring 5. When the limiting ring 5 abuts against the positioning step 491, the limiting ring 5 is perfectly assembled, with the limiting ring 5 coaxial with the column body 4. The spring piece 52 on the inner side of the limiting ring 5 fits perfectly into the first limiting groove 47. Figure 11 As shown, this achieves the purpose of limiting the limiting ring 5, which will not move axially relative to the column 4 and is less likely to fall off the column 4, making assembly simpler and more reliable.

[0060] In implementation, the second column segment 49 can adopt a cylindrical structure, such as... Figure 10 As shown, a square column structure or similar can also be used. In this embodiment, the second column segment 49 can be directly connected to the head 2 and is coaxial with the head 2.

[0061] Compared to bolt 1 in Example 1, this bolt 1 is easier to assemble with the limiting ring 5, thus making the use process simpler and more convenient.

[0062] Example 4

[0063] This embodiment provides a fastening assembly, including the bolt 1 in embodiment 3, and a nut adapted to the screw 3. The nut is threadedly connected to the screw 3 of the bolt 1. In use, the connected part is clamped between the nut and the head 2 to achieve the purpose of fastening.

[0064] To achieve a constant torque effect, in a more refined embodiment, this fastening assembly further includes a limiting ring 5 for the adapter bolt 1 and a constant torque cap 66 for the adapter bolt 1, wherein, as... Figure 6 As shown, the limiting ring 5 includes a ring body 51, a plurality of spring pieces 52 disposed on the inner side of the ring body 51, and a plurality of spring pieces 52 disposed on the outer side of the ring body 51. The spring pieces 52 on the inner side and the spring pieces 52 on the outer side are evenly distributed along the circumference of the ring body 51. In implementation, the inner diameter of the ring body 51 is constructed to be greater than or equal to the outer diameter of the first column segment 48 and less than the outer diameter of the second column segment 49, so that the ring body 51 can be fitted onto the first column segment 48 of the column body 4.

[0065] like Figure 7 As shown, the constant torque cap 66 has an inner hole 61 that fits the cylinder 4. A baffle 62 is provided at one end of the inner hole 61. The baffle 62 is coaxial with the inner hole 61 and is connected to the constant torque cap 66 via at least two connecting posts 63. An insertion hole 64 for inserting the rotary cutting head 43 is formed between adjacent connecting posts 63. Each insertion hole 64 communicates with the inner hole 61. Figure 7 As shown.

[0066] like Figure 11 As shown, the inner hole 61 of the constant torque cap 66 has a second limiting groove 65 adapted to the limiting ring 5 on its side wall.

[0067] During assembly, the limiting ring 5 is first fitted onto the first column segment 48 of the column 4. When the limiting ring 5 abuts against the positioning step 491, the limiting ring 5 is fully engaged. During this process, the spring piece 52 on the inner side of the limiting ring 5 automatically engages into the first limiting groove 47, achieving a reliable connection between the limiting ring 5 and the bolt 1. Then, the column 4 is inserted into the inner hole 61 of the torque cap 66. During insertion, the spring piece 52 on the outer side of the limiting ring 5 automatically engages into the second limiting groove 65, achieving a reliable connection between the limiting ring 5 and the torque cap 66, thereby achieving the connection between the torque cap 66 and the bolt 1. Figure 11 As shown; when inserted into place, each rotary cutting head 43 is inserted into its corresponding socket 64, as shown. Figure 11 As shown.

[0068] During implementation, the parameters of the connecting post 63 need to be accurately calculated and designed, and the connecting post 63 needs to be precisely manufactured according to the design, so that when the connecting post 63 is crushed, the bolt connection can better achieve the required preload value. In use, the torque cap 66 is rotated using a tool, and the torque cap 66 contacts and presses against the contact surface 44 of the rotary cutting head 43 through the connecting post 63, as shown... Figure 11 As shown, the torque cap 66 rotates synchronously with the bolt 1, and the bolt 1 is gradually tightened. When the connecting column 63 is broken by the rotary cutter head 43, the bolt connection reaches the required preload value. At this time, the shield 62 automatically falls off, making the mark 42 at the end of the column 4 visible for subsequent inspection.

[0069] This fastening assembly not only has the advantages of the fastening assembly in Embodiment 2, but also has simpler and more convenient assembly.

[0070] The above description is only a specific embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this utility model should be included within the protection scope of this utility model.

Claims

1. A bolt comprising a head and a threaded rod connected to one end of the head, the threaded rod having external threads, characterized in that, The other end of the head is constructed with a column, and the end of the column is provided with a mark and at least two outwardly protruding rotary cutting heads. Each rotary cutting head is evenly arranged along the circumference of the column and surrounds the mark on the inside. There is a gap between two adjacent rotary cutting heads. The outer surface of the column has a ring-shaped first limiting groove, which is located between the rotary cutting head and the head.

2. The bolt according to claim 1, characterized in that, The column is constructed as a cylindrical structure, with the column and screw coaxial.

3. The bolt according to claim 1, characterized in that, The outer diameter of the column is the same as the outer diameter of the screw.

4. The bolt according to claim 1, characterized in that, A groove is also constructed at the center of the end of the column, and the mark is set in the groove.

5. The bolt according to claim 1, characterized in that, The number of rotary cutting heads is 2-5.

6. The bolt according to claim 1, characterized in that, One side of the rotary cutting head has a contact surface, which is a plane and is coplanar with the central axis of the column.

7. The bolt according to claim 6, characterized in that, The end of the rotary cutting head that is away from the contact surface is the back side, which is constructed as an inclined surface in the vertical direction, and the inclined surface is inclined toward the contact surface; And / or, the rotary cutting head is constructed in an arc shape.

8. The bolt according to claim 1, characterized in that, The column includes a first column segment and a second column segment connected coaxially. A mark and a rotary cutting head are respectively disposed at the end of the first column segment. The first column segment is constructed as a cylindrical structure. The outer diameter of the first column segment is smaller than the outer diameter of the second column segment. A positioning step is formed between the first column segment and the second column segment. The first limiting groove is constructed on the outer side of the first column segment.

9. The bolt according to any one of claims 1-8, characterized in that, The outer surface of the head has a force-bearing structure; The bolt is a one-piece molded component; The markings are color markings or identifiers.

10. A fastening assembly, comprising a nut, characterized in that, It also includes the bolt as described in any one of claims 1-9, wherein the nut is threadedly connected to the bolt.

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