High-assembly-precision torsion shear bolt

Abstract

This utility model discloses a high-precision torque-shear bolt, relating to the field of fastener technology. It includes a bolt head, a bolt shank, a locking head, a fracture groove, and an elastic positioning element. The bolt shank includes a smooth section and an externally threaded section. The locking head is located at the end of the externally threaded section away from the smooth section, and the fracture groove is located between the locking head and the externally threaded section. The elastic positioning element is circumferentially distributed around the smooth section along its axis, with its fixed end connected to the smooth section and its free end extending towards the bolt head. By providing an elastic positioning element around the smooth section of the bolt shank, when the bolt is inserted into the mounting hole, the elastic positioning element enters the hole, contacts the hole wall, and undergoes elastic deformation. A balanced radial elastic force pushes the bolt to automatically center itself. After full insertion, the bolt head fits against the mounting plate, and the positioning element continuously provides radial constraint, solving the problem of poor coaxiality during traditional bolt assembly and making it suitable for high-strength connection scenarios.

Description

Technical Field

[0001] This utility model relates to the field of fastener technology, and in particular to a high-precision torque-shear bolt. Background Technology

[0002] As a core component of high-strength connections, the coaxiality of torque-shear bolts during assembly directly determines the stress uniformity and service life of the connection structure.

[0003] In existing technologies, a 0.5-2mm clearance is typically provided between the mounting hole and the bolt shank to facilitate bolt insertion into the mounting hole of the component to be installed. While this clearance design reduces the difficulty of insertion, it easily leads to poor coaxiality. After bolt insertion, due to the lack of effective radial positioning constraint, its axis is prone to misalignment with the axis of the mounting hole, resulting in uneven distribution of preload along the circumference. Excessive misalignment can cause excessive local stress in the bolt, significantly reducing the fatigue life of the connection, and may even lead to premature bolt fracture under heavy load conditions. Utility Model Content

[0004] Therefore, it is necessary to provide a torque-shear bolt with high assembly precision to address the aforementioned technical problems.

[0005] To achieve the above objectives, this utility model provides a high-precision torque-shear bolt, comprising a screw head, a screw shank, a locking head, a fracture groove, and elastic positioning elements. The screw shank includes a smooth section and a threaded section connected sequentially. The smooth section is connected to the screw head, and the threaded section has external threads. The locking head is located at the end of the threaded section furthest from the smooth section. The fracture groove is located between the locking head and the threaded section. At least three elastic positioning elements are provided, circumferentially distributed around the smooth section along its axis; their fixed ends are connected to the smooth section, and their free ends extend towards the screw head; the distance from their farthest end to the axis of the smooth section is greater than the maximum distance from the fixed end to the smooth section.

[0006] Preferably, the elastic positioning element is elongated, wavy, arc-shaped, or V-shaped.

[0007] Preferably, the cross-section of the elastic positioning element is circular, rectangular, or triangular.

[0008] Preferably, the distance between the fixed end of the elastic positioning member and its free end is less than the distance between the fixed end and the screw head.

[0009] Preferably, the elastic positioning elements are distributed in multiple layers along the axis of the smooth rod section, and the number of elastic positioning elements in each layer is set to at least three.

[0010] The beneficial effects of this technical solution are as follows: By providing an elastic positioning element around the smooth section of the screw, with the free end of the elastic positioning element extending towards the screw head and having an outward expansion design, when the bolt is inserted into the mounting hole, the elastic positioning element enters the hole and contacts the hole wall, generating elastic deformation. Through the circumferentially balanced radial elastic force, the bolt is automatically centered. After full insertion, the screw head fits against the mounting plate, and the positioning element continuously provides radial constraint, solving the problem of poor coaxiality during traditional bolt assembly and making it suitable for high-strength connection scenarios. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of the structure of a torque-shear bolt according to an embodiment of the present invention (the elastic positioning elements are distributed in a single layer).

[0012] Figure 2 for Figure 1 A sectional view along line AA.

[0013] Figure 3 This is a schematic diagram of the structure of a torsion shear bolt according to another embodiment of the present invention (the elastic positioning element is wavy).

[0014] Figure 4 This is a schematic diagram of the structure of a torsion shear bolt according to another embodiment of the present invention (the elastic positioning element is arc-shaped).

[0015] Figure 5 This is a schematic diagram of the structure of a torsion shear bolt according to another embodiment of the present invention (the elastic positioning element is V-shaped).

[0016] Figure 6 This is a schematic diagram of the structure of a torsion shear bolt according to an embodiment of the present invention (the elastic positioning element is distributed in two layers).

[0017] Figure 7 for Figure 6 Installation diagram of torque-shear bolts;

[0018] In the diagram, 1 is the screw head; 2 is the screw rod; 21 is the smooth rod section; 22 is the external thread section; 3 is the snap head; 4 is the fracture groove; 5 is the elastic positioning element; 51 is the fixed end; 52 is the free end; 6 is the washer; 7 is the nut; 8 is the part to be installed; and 81 is the mounting hole. Detailed Implementation

[0019] To make the above-mentioned objects, features, and advantages of this utility model more apparent and understandable, the specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a full understanding of this utility model. However, this utility model can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this utility model. Therefore, this utility model is not limited to the specific embodiments disclosed below.

[0020] Please see Figures 1 to 7 This application provides a high-precision torque-shear bolt, including a bolt head 1, a bolt shank 2, a locking head 3, a fracture groove 4, and an elastic positioning element 5.

[0021] The screw section 2 includes a smooth rod section 21 and an external thread section 22 connected in sequence. The smooth rod section 21 is connected to the screw head 1, and the external thread section 22 is provided with external threads for cooperating with the nut 7 to achieve locking.

[0022] The clamping head 3 is located at the end of the external thread section 22 away from the smooth rod section 21, and its outer circumferential surface is provided with evenly distributed serrations for engaging with the sleeve of the torque shear wrench. The outer diameter of the clamping head 3 is smaller than the outer diameter of the screw section 2.

[0023] The fracture groove 4 is located between the clamp head 3 and the external thread section 22; its cross-section is V-shaped or U-shaped, and the thickness of the groove bottom is designed according to the preset fracture torque, usually 2-5mm, to ensure that the clamp head breaks along the bottom of the groove when the torque reaches the preset value. During installation, a torque is applied to the clamp head 3 using a torque shear wrench. When the torque reaches the predetermined value, the clamp head 3 breaks at the fracture groove 4 and falls off, thereby controlling the preload of the bolt.

[0024] Four elastic positioning elements 5 are provided and are distributed in a circle around the outer periphery of the smooth rod section 21 along the axis of the smooth rod section 21; their fixed ends 51 are connected to the smooth rod section 21, and their free ends 52 extend towards the screw head 1; the distance of their farthest end from the axis of the smooth rod section 21 is greater than the maximum distance of the fixed end 51 from the smooth rod section 21.

[0025] The elastic positioning component 5 is made of spring steel, such as 65Mn or titanium alloy, with a tensile strength of 500-800MPa and an elastic deformation of not less than 10%. The fixed end 51 of the elastic positioning component 5 is connected to the outer wall of the smooth rod section 21 by welding. The distance from the farthest end of the free end 52 to the axis of the smooth rod section 21 is greater than the maximum distance from the fixed end 51 to the axis of the smooth rod section 21, specifically 0.3-1mm, thereby forming an outwardly expanding elastic support structure. After being inserted into the mounting hole 81, it contacts the hole wall of the mounting hole 81 and generates elastic deformation.

[0026] In this embodiment, please refer to Figure 1 , Figure 2 , Figure 6and Figure 7 The elastic positioning element 5 is set to be elongated, and the cross-section of the elastic positioning element 5 is circular. At this time, the farthest end of the elastic positioning element 5 is its free end 52.

[0027] For example, the elastic positioning element 5 has a length of 10-20mm and a diameter of 2mm, which results in a simple structure and low processing cost. The distance from the fixed end 51 to the free end 52 of the elastic positioning element 5 is 15mm, and the distance from the fixed end 51 to the screw head 1 is 20mm. The angle between the elastic positioning element 5 and the smooth rod section 21 is 10 degrees, ensuring that when the bolt is almost fully inserted, the elastic positioning element 5 enters the mounting hole 81 and contacts the hole wall before the screw head 1. Subsequently, the free end 52 moves closer to the smooth rod section 21, and the distance between the free end 52 and the screw head 1 decreases. After the screw head 1 contacts the mounting plate, the alignment is completed, and after the screw head 1 contacts the mounting plate, the free end 52 of the elastic positioning element 5 does not contact the screw head 1.

[0028] Working principle:

[0029] 1. Tail-end insertion stage: The bolt is inserted into the mounting hole 81 of the component to be installed 8 with the clamp head 3 as the pilot end. Since there is a reasonable gap between the external thread section 22, the smooth rod section 21 and the mounting hole 81, the insertion process is smooth and can be quickly pushed forward without precise alignment.

[0030] 2. Positioning component contact stage: When the bolt is almost fully inserted, the elastic positioning component 5 on the periphery of the smooth rod section 21 enters the mounting hole 81. Its free end 52 contacts the hole wall due to the outward expansion design. As the bolt continues to be inserted, the elastic positioning component 5 is squeezed by the hole wall and undergoes elastic deformation. The amount of deformation matches the fitting clearance. The radial elastic force generated at this time provides the initial power for centering.

[0031] 3. Automatic alignment stage: The elastic positioning element 5 is continuously subjected to the reaction force of the hole wall. Since the three elastic positioning elements 5 are evenly distributed along the circumference, the elastic forces in each direction form a balanced torque, which pushes the bolt to automatically adjust its posture, so that the bolt axis gradually coincides with the axis of the mounting hole 81.

[0032] 4. Screw head engagement stage: After the bolt is fully inserted, the end face of the screw head 1 contacts the surface of the mounting plate. At this time, the elastic positioning element 5 still maintains elastic contact with the hole wall, forming a stable radial constraint to ensure that the bolt is always in the center before pre-tightening.

[0033] 5. Pre-tightening and breakage stage: After the washer 6 is installed on the screw part 2, the nut 7 is screwed in. During the tightening of the nut 7, the elastic support of the elastic positioning part 5 prevents the bolt from shifting due to the pre-tightening force, ensuring that the pre-tightening force is evenly distributed along the circumference. When the torque is applied to the preset value by the torque shear wrench, the breakage groove 4 breaks and the clamp head 3 falls off, completing the pre-tightening.

[0034] In some other embodiments, the elastic positioning element 5 may also be wavy, arc-shaped, or V-shaped.

[0035] like Figure 3 As shown, when the elastic positioning element 5 is wavy, its farthest end is its free end 52. Optimizing the elastic deformation characteristics through the wavy structure can improve adaptability to different aperture deviations.

[0036] like Figure 4 As shown, when the elastic positioning element 5 is arc-shaped, its radius of curvature is 1.1-1.3 times the radius of the mounting hole 81, resulting in better positioning stability. At this time, the farthest end of the elastic positioning element 5 is between its free end 52 and fixed end 51.

[0037] like Figure 5 As shown, when the elastic positioning member 5 is V-shaped, its V-shaped opening faces the center of the smooth rod section 21, which reduces the risk of insertion jamming while ensuring the positioning effect. At this time, the farthest end of the elastic positioning member 5 is at the tip of its V-shaped structure.

[0038] The cross-section of the elastic positioning element 5 can also be rectangular, triangular, or elliptical.

[0039] When the cross-section of the elastic positioning member 5 is rectangular, for example, its cross-section length is 2-5mm and its width is 1-3mm;

[0040] When the cross-section of the elastic positioning member 5 is triangular, for example, its cross-sectional side length is 2-4mm, and the tip faces the wall of the mounting hole 81.

[0041] In some embodiments, such as Figure 6 and Figure 7 As shown, the elastic positioning elements 5 are distributed in multiple layers along the axis of the smooth rod section 21, with at least three elastic positioning elements 5 in each layer. These multiple layers of elastic positioning elements 5 can form radial constraints at different depths when the bolt is inserted into the mounting hole 81, avoiding the problem of misalignment at both ends due to a single layer of positioning. Especially for longer bolts, the multi-layer distribution allows for segmented alignment, ensuring that the bolt section 2 remains coaxial with the mounting hole 81 throughout its length, further reducing coaxiality errors.

[0042] The multi-layer elastic positioning element 5 can distribute the radial positioning force to multiple axial positions of the smooth rod section 21, avoiding excessive deformation or fatigue failure of a single-layer positioning element due to concentrated force.

[0043] In addition, when the nut 7 is tightened, the bolt may have a slight bending tendency due to the axial preload. The multi-layer elastic positioning element 5 forms a multi-point anti-bending constraint through radial support at different axial positions, which effectively suppresses bolt tilting and ensures that the preload is evenly transmitted along the contact surface between the bolt head 1 and the mounting plate, reducing stress distribution deviation.

[0044] The multi-layered elastic positioning components 5 can also form a positioning function redundancy. Even if a positioning component in one layer fails locally due to processing errors or burrs on the wall of the mounting hole 81, the remaining layers can still maintain the basic positioning function, avoiding coaxiality loss due to single-point failure and improving the reliability and fault tolerance of the assembly process.

[0045] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0046] The above embodiments only illustrate several implementation methods of this utility model, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model patent should be determined by the appended claims.

[0047] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0048] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this utility model, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0049] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

Claims

1. A high-precision torque-shear bolt, characterized in that, include: Screw head (1); The screw section (2) includes a smooth rod section (21) and an external thread section (22) connected in sequence. The smooth rod section (21) is connected to the screw head (1), and the external thread section (22) is provided with external threads. The card head (3) is located at the end of the external thread section (22) away from the smooth rod section (21); The fracture groove (4) is located between the card head (3) and the external thread section (22); At least three elastic positioning elements (5) are provided and are distributed in a circular pattern around the outer periphery of the smooth rod section (21) along the axis of the smooth rod section (21); their fixed ends (51) are connected to the smooth rod section (21), and their free ends (52) extend toward the screw head (1); the distance from the farthest end of the free end to the axis of the smooth rod section (21) is greater than the maximum distance from the fixed end (51) to the smooth rod section (21).

2. The high-precision torque-shear bolt according to claim 1, characterized in that, The elastic positioning element (5) is elongated.

3. The high-precision torque-shear bolt according to claim 1, characterized in that, The elastic positioning element (5) is wavy.

4. The high-precision torque-shear bolt according to claim 1, characterized in that, The elastic positioning element (5) is arc-shaped.

5. The high-precision torque-shear bolt according to claim 1, characterized in that, The elastic positioning element (5) is V-shaped.

6. The high-precision torque-shear bolt according to any one of claims 1 to 5, characterized in that, The cross-section of the elastic positioning element (5) is circular.

7. The high-precision torque-shear bolt according to any one of claims 1 to 5, characterized in that, The cross-section of the elastic positioning element (5) is rectangular.

8. The high-precision torque-shear bolt according to any one of claims 1 to 5, characterized in that, The cross-section of the elastic positioning element (5) is triangular.

9. The high-precision torque-shear bolt according to claim 1, characterized in that, The distance between the fixed end (51) of the elastic positioning member (5) and its free end (52) is less than the distance between the fixed end (51) and the screw head (1).

10. The high-precision torque-shear bolt according to claim 1, characterized in that, The elastic positioning element (5) is distributed in multiple layers along the axis of the smooth rod section (21), and the number of elastic positioning elements (5) in each layer is set to at least three.

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