Single-sided connecting bolt, and mounting tool and mounting method therefor

Abstract

Disclosed are a single-sided connecting bolt (100), and a mounting tool and a mounting method therefor. The single-sided connecting bolt (100) comprises: a bolt body portion (1), which comprises a first unthreaded shank body (11), wherein a first countersunk portion (12) is arranged on one end of the first unthreaded shank body (11), and an end face of the first countersunk portion (12) is configured as a wrenching-groove-free ring surface (13); a core rod portion (2), which comprises a second unthreaded shank body (21) and a second countersunk portion (22), wherein an external threaded portion (23) is provided on a second end of the second unthreaded shank body (21), the second countersunk portion (22) is connected to a core rod head portion (25) by means of a breakable neck groove portion (24), and an annular tension-bearing flat surface (251) is provided on the end face of the core rod head portion (25) close to the breakable neck groove portion (24), so as to increase the load-bearing area between the mounting tool and the core rod head portion; a bolt sleeve portion (3); and a nut portion (4), wherein the external threaded portion (23) of the core rod portion (2) passes through the bolt sleeve portion (3) and is then threadedly connected to the nut portion (4). The end face of the bolt body portion of the single-sided connecting bolt uses a groove-free design, and the mounting tool is designed to match therewith, enabling the complete mounting of the single-sided connecting bolt; after mounting, the overall surface of the machine part to which the bolt is connected is flat, such that the aerodynamic performance is improved, and the fatigue and tensile performance of the single-sided connecting bolt are improved.

Description

Single-sided connecting bolt and installation tool and installation method thereof

[0001] The present disclosure claims priority to the Chinese patent application No. 202411894439.3, filed on December 20, 2024, and entitled "Single-sided connecting bolt and installation tool and installation method thereof", the entire content of which is incorporated herein by reference. TECHNICAL FIELD

[0002] The present disclosure relates to the technical field of fasteners, in particular to a single-sided connecting bolt and installation tool and installation method thereof. BACKGROUND

[0003] The single-sided connecting bolt has the same shear strength as a traditional bolt, and has the same tensile fatigue, clamping force, anti-loosening and anti-vibration, lightning protection and other performances as an anti-shear high-lock bolt / high-lock nut combination. The single-sided connecting bolt has a large diameter and high strength, and good fatigue performance, and can be installed on one side like a common core-pulling rivet. After installation, the cross section is smooth, and no additional polishing process is required. Compared with the high-lock bolt, the single-sided connecting bolt has a wider range of use for the same interlayer length, and the maximum allowable inclination angle of the structural surface can reach 7°. The single-sided connecting bolt is recommended for high-shear load connection, and can also be used in areas with poor process path and insufficient installation space. During installation of the single-sided connecting bolt, the pin body is fixed by the installation gun head clamping jaw to prevent the pin body from rotating, the core rod is driven to rotate by the installation gun, the nut moves towards the pin body, the pin sleeve gradually expands and deforms along the taper angle of the pin body, and contacts the interlayer surface to form a upset head. When the upset head is large enough, the reaction force applied to the core rod through the deformation of the pin sleeve exceeds the twisting force provided by the neck fracture groove, the core rod breaks, and the broken part is separated from the core rod. At this time, the installation process is completed.

[0004] The existing single-sided connecting bolt and installation method have the following problems.

[0005] 1. During installation and forming of the single-sided connecting bolt, 30% of the friction force to be overcome comes from the friction force formed between the core rod and the pin body countersunk part during forming of the pin sleeve. Therefore, reducing the friction force between the core rod and the pin body countersunk part is beneficial to the forming of the pin sleeve, can reduce the diameter of the neck fracture groove, and improve the comfort of installation operation.

[0006] 2. The pin body twisting groove of the single-sided connecting bolt is very small, and the installation gun clamping jaw is not easy to align with the pin body twisting groove. After the installation gun is started, the pin body twisting groove is scratched, which leads to installation failure.

[0007] 3. When the small-specification countersunk single-sided connecting bolt is broken in fatigue or tension, it is easy to break at the pin body twisting groove.

[0008] 4. After the single-sided connecting bolts are installed, there are four screw-tightening grooves on the broken surface of the nail body, which are not flat enough and affect the aerodynamic performance and surface flatness of the fuselage.

[0009] Therefore, based on years of experience and practice in related industries, the inventor proposes a single-sided connecting bolt and its installation tools and methods to overcome the shortcomings of existing technologies. Summary of the Invention

[0010] The purpose of this disclosure is to provide a single-sided connecting bolt, its installation tool, and installation method. The end face of the bolt body of the single-sided connecting bolt of this disclosure adopts a grooveless design, and the installation tool is designed to match it, so as to realize the complete installation of the single-sided connecting bolt. After installation, the overall surface of the machine body is flat, the aerodynamic performance is improved, and the fatigue and tensile performance of the single-sided connecting bolt are enhanced.

[0011] The purpose of this disclosure is achieved as follows: a single-sided connecting bolt includes: a nail body portion fixedly inserted into a component to be connected, the nail body portion including a first smooth rod body, a first countersunk head provided at a first end of the first smooth rod body, the end face of the first countersunk head being a non-tightening groove annular surface; a nail body central hole provided axially within the first smooth rod body, and a countersunk hole provided within the first countersunk head; a core rod portion including a second smooth rod body inserted into the nail body central hole, a second countersunk head provided at a first end of the second smooth rod body corresponding to the countersunk hole, and an external threaded portion at a second end of the second smooth rod body; the second countersunk head is... The core rod head is connected via a necked groove. An annular bearing plane is provided on the end face of the core rod head near the necked groove to increase the bearing area between the installation tool and the core rod head. A nail sleeve is provided; the first end of the nail sleeve can move inward from the second end of the first smooth rod body and can radially deform to abut against the component to be connected. A nut is abutted against the second end of the nail sleeve. An external threaded portion passes through the nail sleeve and is threadedly connected to the nut. The core rod rotates to move the nut towards the nail body for tightening, and the nut pushes the nail sleeve to move and deform. A locking structure is provided on the nut.

[0012] In some preferred embodiments of this disclosure, a ring is sleeved on the inner side of the first end of the nail sleeve portion, and the ring can deform with the first end of the nail sleeve portion to abut against the member to be connected.

[0013] In some preferred embodiments of this disclosure, the second end of the first guide rod body is provided with a tapered anti-slip groove with a gradually decreasing diameter. The tapered anti-slip groove is used for guiding the movement of the first end of the nail sleeve and for radial extrusion deformation.

[0014] In some preferred embodiments of this disclosure, the end face of the second end of the nail sleeve is provided with a first anti-slip tooth, and the end face of the nut near the nail sleeve is provided with a second anti-slip tooth that can abut and engage with the top of the first anti-slip tooth.

[0015] In some preferred embodiments of this disclosure, the locking structure includes at least one locking recess structure disposed on the side wall of the nut portion, the radially inner end of the locking recess structure protruding from the internal thread portion of the nut portion, and the locking recess structure is used to lock the external thread portion of the core rod portion.

[0016] In some preferred embodiments of this disclosure, the surface roughness of the first sinker head is greater than or equal to Ra6.3.

[0017] In some preferred embodiments of this disclosure, the nail body is made of titanium alloy.

[0018] This disclosure can also be implemented as follows: an installation tool for the aforementioned single-sided connecting bolt includes: a torque wrench, including a wrench body, the wrench body having a torque output part; a working sleeve, detachably connected to the torque wrench; the working sleeve includes an outer sleeve, a first end of the outer sleeve being fixedly connected to the wrench body, and the end face of the second end of the outer sleeve being able to abut and press against the non-tightening groove annular surface of the first countersunk head; a wrench clamping structure for rotating and transmitting torque is provided inside the outer sleeve, the first end of the wrench clamping structure being fixedly connected to the torque output part, the second end of the wrench clamping structure being able to be sleeved on the core rod head, and the second end of the wrench clamping structure having an axial pulling part, the axial pulling part being able to axially abut against the annular bearing plane and pull the core rod head towards the torque output part.

[0019] In some preferred embodiments of this disclosure, the outer sleeve includes a fixed sleeve connected to the wrench body, and a movable sleeve that is circumferentially fixed and axially movable along the fixed sleeve passes through one end of the fixed sleeve away from the wrench body. The end face of the movable sleeve away from the fixed sleeve can press against the untightened groove annular surface of the first countersunk head.

[0020] In some preferred embodiments of this disclosure, the wrench clamping structure includes a wrench head that can be sleeved on the head of the core rod, the wrench head being connected to the torque output part via a torque transmission shaft; a radially elastically deformable chuck is provided at the end of the wrench head away from the torque transmission shaft, the chuck being radially contractible to clamp the broken neck groove; a radially reduced locking step is provided at the end of the chuck away from the torque transmission shaft, the locking step constituting the axial pulling part, the locking step being able to abut against the annular bearing plane; an external thread is provided on the outer wall of the torque transmission shaft, an internal thread is provided on the inner wall of the movable sleeve, the torque transmission shaft and the movable sleeve constituting a screw-nut structure, the rotation of the torque transmission shaft being converted into axial movement of the movable sleeve.

[0021] In some preferred embodiments of this disclosure, a guide key is provided on the inner wall of the fixed sleeve, and a guide groove is provided on the outer wall of the movable sleeve, which is slidably fitted onto the guide key.

[0022] In some preferred embodiments of this disclosure, the roughness of the end face of the movable sleeve away from the fixed sleeve is greater than or equal to Ra12.5.

[0023] In some preferred embodiments of this disclosure, the outer sleeve includes a support sleeve connected to the wrench body, one end of the support sleeve away from the wrench body is connected to an outer end sleeve, and the end face of the outer end sleeve can press against the untightened groove annular surface of the first countersunk head; a hollow gun head that can move axially is provided inside the support sleeve.

[0024] In some preferred embodiments of this disclosure, the wrench clamping structure includes a wrench head that can be sleeved on the head of the core rod, the wrench head being connected to the torque output part via a drive linkage; the wrench head and the drive linkage are rotatably disposed within the gun head; a rotor sleeve that can rotate with the core rod is sleeved on the outer side of the wrench head, and a thrust bearing is disposed between the rotor sleeve and the support sleeve; one end of the rotor sleeve away from the torque output part can be locked into the necking groove, and the axial pulling part includes a stepped surface disposed on the rotor sleeve that can axially abut against the annular bearing plane.

[0025] In some preferred embodiments of this disclosure, the roughness of the end face of the outer end sleeve is greater than or equal to Ra12.5.

[0026] This disclosure can also be implemented as follows: an installation method for the aforementioned single-sided connecting bolt includes: fixing the bolt body to the mounting hole on the part to be connected by adhesive bonding or interference connection; passing the core rod through the first countersunk head of the bolt body to the other end; sequentially arranging the bolt sleeve and the nut at the other end of the bolt body; threading the core rod through the bolt body and the bolt sleeve to the nut; and driving the nut and the bolt sleeve to move towards the part to be connected and tighten by rotating the core rod.

[0027] As described above, the single-sided connecting bolt, its installation tools, and installation method disclosed herein have the following beneficial effects.

[0028] Unlike existing single-sided connecting bolts, this disclosure removes the four wrench grooves on the end face of the bolt body, making it a grooveless single-sided connecting bolt. The end face of the first countersunk head is set as a grooveless annular surface, resulting in a flat cross-section after installation and improved fatigue and tensile properties. After installation, the overall fuselage is smoother, improving the aircraft's aerodynamic performance.

[0029] The neck groove of the core rod disclosed herein adopts a special design. An annular bearing plane is provided on the end face of the core rod head near the neck groove. The neck groove can withstand greater tensile force, which allows the core rod to be lifted during installation and reduces the friction between the core rod and the nail body.

[0030] When using the installation tool disclosed herein to install a single-sided connecting bolt, the friction coefficient between the installation tool and the end face of the bolt body is increased throughout the installation process. The installation tool presses the end face of the bolt body to keep it stationary during installation. The installation tool also applies tension to the core rod, reducing the friction between the countersunk hole of the bolt body and the core rod. This helps to reduce forming resistance, improve installation stability and reliability, and ensure the smooth completion of the installation process. Attached Figure Description

[0031] The accompanying drawings are intended only to illustrate and explain this disclosure and do not limit the scope of this disclosure.

[0032] Figure 1 is a schematic diagram of the assembly of the single-sided connecting bolt of this disclosure;

[0033] Figure 2 is an exploded view of the single-sided connecting bolt of this disclosure;

[0034] Figure 3 is a side view of the single-sided connecting bolt of this disclosure;

[0035] Figure 4 is a schematic diagram of Embodiment 1 of the installation tool for the single-sided connecting bolt of this disclosure;

[0036] Figure 5a is a schematic diagram of the working sleeve of Embodiment 1 of the installation tool for the single-sided connecting bolt of this disclosure;

[0037] Figure 5b is a schematic diagram of the wrench head and torque transmission shaft of this disclosure;

[0038] Figure 5c is a half-sectional view of the movable sleeve of this disclosure;

[0039] Figure 5d is a side view of the movable sleeve of this disclosure;

[0040] Figure 5e is a schematic diagram of the process of inserting the wrench head and torque transmission shaft into the movable sleeve of this disclosure;

[0041] Figure 6 is a schematic diagram of Embodiment 2 of the installation tool for the single-sided connecting bolt of this disclosure;

[0042] Figure 7 is a schematic diagram of the working sleeve of Embodiment 2 of the installation tool for the single-sided connecting bolt of this disclosure;

[0043] Figure 8 is an external schematic diagram of Embodiment 2 of the installation tool for the single-sided connecting bolt of this disclosure;

[0044] Figure 9a shows the initial installation state of the single-sided connecting bolt of this disclosure;

[0045] Figure 9b is a diagram showing the state when the staple sleeve of this disclosure is not in contact with the interlayer;

[0046] Figure 9c is a diagram showing the state after the staple sleeve and the interlayer of this disclosure are clamped together;

[0047] Figure 9d is a diagram showing the state of the single-sided connecting bolts in the later stage of installation according to this disclosure;

[0048] Figure 10 is a schematic diagram of the installation process of the single-sided connecting bolt of this disclosure.

[0049] Explanation of reference numerals in the attached drawings: 100, Single-sided connecting bolt; 200, Installation tool for single-sided connecting bolt; 1, Bolt body; 11, First smooth rod body; 12, First countersunk head; 13, Unscrew-free groove annular surface; 14, Bolt body center hole; 15, Countersunk hole; 16, Tapered anti-slip groove; 2, Core rod; 21, Second smooth rod body; 22, Second countersunk head; 23, External thread; 24, Neck break groove; 25, Core rod head; 251, Annular bearing plane; 3, Bolt sleeve; 31, First anti-slip groove. 4. Slippery tooth; 41. Nut part; 42. Second anti-slip tooth; 43. Locking socket structure; 5. Ring; 6. Torque wrench; 61. Wrench body; 62. Torque output part; 71. Fixed sleeve; 72. Movable sleeve; 721. Inner conical hole; 722. Guide groove; 73. Support sleeve; 74. Outer end sleeve; 75. Gun head; 81. Tightening head; 811. Locking step part; 82. Torque transmission shaft; 83. Drive connecting rod; 84. Rotor sleeve; 85. Thrust bearing; 9. Interlayer. Detailed Implementation

[0050] To provide a clearer understanding of the technical features, objectives, and effects of this disclosure, specific embodiments of this disclosure will now be described with reference to the accompanying drawings.

[0051] The specific embodiments of this disclosure described herein are for illustrative purposes only and should not be construed as limiting the scope of this disclosure in any way. Under the teachings of this disclosure, those skilled in the art can conceive of any possible modifications based on this disclosure, all of which should be considered within the scope of this disclosure. It should be noted that when an element is referred to as being "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or there may be an intervening element. The terms "mounted," "connected," and "linked" should be interpreted broadly; for example, they can refer to mechanical or electrical connections, or internal communication between two elements, and can be direct or indirect connections through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible embodiments.

[0052] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0053] As shown in Figures 1, 2, and 3, this disclosure provides a single-sided connecting bolt 100, which is a single-sided connecting bolt without end grooves, including a nail body 1, a core rod 2, a neck groove 24, a nail sleeve 3, and a nut 4, which are fixedly inserted into the parts to be connected.

[0054] The nail body 1 includes a first smooth rod body 11, a first countersunk head 12 is provided at the first end of the first smooth rod body 11, and the end face of the first countersunk head 12 is provided as a non-tightening groove annular surface 13; a nail body center hole 14 is provided axially in the first smooth rod body 11, and a countersunk hole 15 is provided in the first countersunk head 12.

[0055] The core rod portion 2 includes a second smooth rod body 21 passing through the central hole 14 of the nail body. A second countersunk head 22 corresponding to the countersunk hole 15 is provided at the first end of the second smooth rod body 21, and an external thread portion 23 is provided at the second end of the second smooth rod body 21. The second countersunk head 22 is connected to the core rod head 25 via a necked groove 24. An annular bearing plane 251 is provided on the end face of the core rod head 25 near the necked groove 24 to increase the bearing area between the installation tool and the core rod head 25. This structure increases the bearing area of ​​the core rod head 25 in contact with the installation tool, ensuring the strength of the necked groove 24 during the riveting installation process, making the core rod portion 2 more reliable under tensile force. The installation tool exerts a tensile force on the core rod head 25 in a direction away from the nail body portion 1, creating a gap between the outer wall of the second countersunk head 22 and the inner wall of the countersunk hole 15, reducing the contact between the core rod portion 2 and the nail body portion 1, thereby reducing friction during installation.

[0056] The neck groove 24 serves to transmit driving force during the installation of the single-sided connecting bolt 100. The neck groove 24 disclosed herein has an increased bearing surface compared to a conventional neck groove. The second smooth rod body 21 mainly mates with the center hole 14 of the nail body and has high shear strength. The external threaded part 23 is the main load-bearing part during installation and is threadedly connected to the nut part 4.

[0057] The first end of the nail sleeve 3 can move inward from the second end of the first guide rod body 11 and can radially deform to abut against the part to be connected.

[0058] The nut part 4 is abutted against the second end of the nail sleeve part 3; the external thread part 23 passes through the nail sleeve part 3 and is threadedly connected to the nut part 4; the core rod part 2 rotates to drive the nut part 4 to move and tighten towards the nail body part 1, and the nut part 4 pushes the nail sleeve part 3 to move and deform; a locking structure is provided on the nut part 4.

[0059] During movement, the nut part 4 pushes the nail sleeve part 3 to displace, causing the nail sleeve part 3 to deform and form a large base. The locking structure prevents the single-sided connecting bolt 100 from loosening under load and vibration after installation.

[0060] Unlike existing single-sided connecting bolts, this disclosure removes the four wrench grooves on the end face of the bolt body, and the end face of the first countersunk head 12 is set as a non-wrench groove annular surface 13. After installation, the cross-section is flat, and the fatigue and tensile properties are improved.

[0061] The neck groove 24 of the core rod in this disclosure adopts a special design. An annular bearing plane 251 is provided on the end face of the core rod head 25 near the neck groove 24. The neck groove 24 can withstand greater tensile force, which can meet the requirement of lifting the core rod during installation and reducing the friction between the core rod and the nail body.

[0062] Furthermore, as shown in Figures 1 and 2, a ring 5 is fitted inside the first end of the nail sleeve 3. The ring 5 can deform with the first end of the nail sleeve 3 and press against the part to be connected. The ring 5 serves to fill and support the deformation of the nail sleeve 3, deforming together with the nail sleeve 3 to form a large base, and finally clamping the part to be connected.

[0063] Furthermore, as shown in Figure 2, a tapered anti-slip groove 16 with a gradually decreasing diameter is provided at the second end of the first optical rod body 11. The tapered anti-slip groove 16 is used for the movement guidance and radial expansion deformation of the first end of the nail sleeve.

[0064] Furthermore, as shown in Figure 2, a first anti-slip tooth 31 is provided on the end face of the second end of the nail sleeve portion 3, and a second anti-slip tooth 41 is provided on the end face of the nut portion 4 near the nail sleeve portion 3, which can abut and engage with the first anti-slip tooth 31. The nail sleeve portion 3 and the nut portion 4 achieve axial compression and circumferential relative fixation through the engagement of the first anti-slip tooth 31 and the second anti-slip tooth 41, preventing slippage during installation.

[0065] Further, as shown in Figure 2, the locking structure includes at least one locking recess structure 42 disposed on the side wall of the nut portion 4. The radially inner end of the locking recess structure 42 is provided in such a way that it protrudes from the internal thread portion of the nut portion 4. The locking recess structure 42 is used to lock the external thread portion of the core rod portion. In a specific embodiment, three locking recess structures 42 are evenly distributed on the side wall of the nut portion 4 at circumferential intervals of 120°.

[0066] In this disclosure, the four wrench grooves on the end face of the nail body are removed, and the end face of the first countersunk head 12 is set as a non-wrench groove annular surface 13. In order to ensure that the nail body 1 is fixed during installation, it is necessary to increase the friction between the installation tool and the non-wrench groove annular surface 13. Roughening the end face of the first countersunk head 12 is an effective way.

[0067] Furthermore, the nail body 1 is made of titanium alloy.

[0068] In one specific embodiment, the nail body 1 is made of titanium alloy TC4. The nail body 1 is formed by upsetting. The upsetting die structure is reasonably designed. After upsetting, the end face of the first countersunk head 12 is roughened. The roughness is increased from the original Ra1.6 to Ra6.3 or greater, so as to increase the friction coefficient of the installation contact surface (the end face of the installation tool and the ring surface 13 without wrench groove).

[0069] As shown in Figures 4, 5a, 6, 7, and 8, this disclosure also provides an installation tool 200 for a single-sided connecting bolt, including a torque wrench 6 and a working sleeve.

[0070] The torque wrench 6 includes a wrench body 61, on which a torque output part 62 is provided; the power source of the torque wrench 6 comes from pneumatic or electric power.

[0071] The working sleeve is detachably connected to the torque wrench 6; the working sleeve includes an outer sleeve, the first end of which is fixedly connected to the wrench body 61, and the end face of the second end of the outer sleeve can press against the non-grooved annular surface 13 of the first countersunk head 12.

[0072] A wrench clamping structure for transmitting torque by rotation is installed inside the outer casing. The first end of the wrench clamping structure is fixedly connected to the torque output part 62, and the second end of the wrench clamping structure can be sleeved on the core rod head 25. Furthermore, an axial pulling part is provided at the second end of the wrench clamping structure. The axial pulling part can axially abut against the annular bearing plane 251 and pull the core rod head 25 in the direction of the torque output part 62, ensuring that a tensile force is applied to the core rod part 2 during installation.

[0073] Sufficient positive pressure is applied to the end face of the nail body 1 by the installation tool, and the core rod 2 is raised simultaneously. This reduces the friction between the core rod 2 and the countersunk hole 15 of the nail body 1, and overcomes the deformation resistance generated by the gradual deformation of the nail sleeve 3. The deformation resistance of the nail sleeve 3 is converted into the friction between the core rod 2 and the nail body 1 and the covering force on the nail body 1, ensuring that the nail body 1 does not rotate with the core rod 2 during installation, thus achieving complete installation.

[0074] The single-sided connecting bolt installation tool 200 disclosed herein has an outer sleeve that presses against and tightens against the slotless annular surface 13 of the first countersunk head 12. Pressure is applied to the end face of the bolt body 1 through the outer sleeve, fixing the bolt body 1 in place during installation. Simultaneously, the core rod 2 is tensioned by the axial pulling part, reducing the friction between the second countersunk head 22 of the core rod 2 and the countersunk hole 15 of the bolt body 1. This helps reduce the forming resistance of the bolt sleeve 3, improving installation stability and reliability, ultimately achieving the installation of the slotless single-sided connecting bolt 100.

[0075] Example 1

[0076] As shown in Figures 4 and 5a, the outer sleeve includes a fixed sleeve 71 connected to the wrench body 61. A movable sleeve 72, which is circumferentially fixed and can move axially along the fixed sleeve 71, is provided at the end of the fixed sleeve 71 away from the wrench body 61. The end face of the movable sleeve 72 away from the fixed sleeve 71 can press against the non-tightening groove annular surface 13 of the first countersunk head 12.

[0077] Further, as shown in Figures 4, 5a, 5b, and 5e, the wrench clamping structure includes a wrench head 81 that can be sleeved on the head 25 of the core rod. The wrench head 81 is connected to the torque output part 62 via the torque transmission shaft 82. A radially elastically deformable chuck is provided at the end of the wrench head 81 away from the torque transmission shaft 82 (i.e., an opening groove is provided on the side wall of the sleeve, so that its opening end is elastic and can expand and contract radially; when installing the chuck into the movable sleeve 72, it is first manually retracted, and after being inserted into the movable sleeve 72, it expands radially with its inner cavity). The chuck can radially retract to clamp the necked groove 24. A radially reduced locking step part 811 is provided at the end of the chuck away from the torque transmission shaft 82. The locking step part 811 constitutes the aforementioned axial pulling part and can abut against the annular bearing plane 251. An external thread is provided on the outer wall of the torque transmission shaft 82, and an internal thread is provided on the inner wall of the movable sleeve 72. The torque transmission shaft 82 and the movable sleeve 72 form a screw and nut structure, and the rotation of the torque transmission shaft 82 can be converted into the axial movement of the movable sleeve 72.

[0078] Furthermore, as shown in Figures 5a and 5d, a guide key is provided on the inner wall of the fixed sleeve 71, and a guide groove 722 that can be slidably fitted onto the guide key is provided on the outer wall of the movable sleeve 72.

[0079] Furthermore, as shown in Figure 5c, an inner conical hole 721 with a gradually decreasing diameter is provided inside the movable sleeve 72 from the end away from the fixed sleeve 71 inward. The inner conical hole 721 can radially press the chuck jaws to clamp the necked groove 24. The cone angle of the inner conical hole 721 is 6°. When the chuck jaws of the wrench head 81 move within the inner conical hole 721, their radial dimensions change.

[0080] When installing a single-sided connecting bolt using the installation tool of Embodiment 1, firstly, the end face of the movable sleeve 72 is pressed against and tightened onto the non-tightening groove annular surface 13 of the first countersunk head 12. The core rod head 25 is fitted into the chuck of the wrench head 81, and the chuck radially retracts to clamp the necked groove 24. The torque wrench 6 is activated, and the torque output part 62 drives the torque transmission shaft 82, the wrench head 81, and the core rod part 2 to rotate. Due to the interaction between the torque transmission shaft 82 and the movable sleeve 72, the torque of the torque transmission shaft 82 is converted into an axial force on the movable sleeve 72, causing the movable sleeve 72 to press against the non-tightening groove annular surface 13 of the bolt body part 1. At the same time, the torque transmission shaft 82, the wrench head 81, and the core rod 2 are subjected to the reverse axial force of the movable sleeve 72. The core rod head 25 is pulled backward, and a gap of about 0.1mm is formed between the second countersunk head 22 of the core rod 2 and the countersunk hole 15 of the nail body 1, reducing the contact between the core rod 2 and the nail body 1, thereby reducing the friction force on the core rod 2 during installation.

[0081] The torque output part 62 rotates, the nail sleeve part 3 gradually deforms, and when the nail sleeve part 3 is formed to a sufficiently large size, the neck groove part 24 is twisted off, and the single-sided connecting bolt 100 is installed.

[0082] To improve the clamping stability of the outer sleeve on the nail sleeve 3 and increase the friction between the installation tool and the wrenchless screw groove annular surface 13, the abutting end faces of the outer sleeve and the nail sleeve 3 can be roughened. The roughness of the end face of the movable sleeve 72 away from the fixed sleeve 71 is greater than or equal to Ra12.5. The outer sleeve is made of special materials to ensure a high coefficient of friction, wear resistance, and long service life.

[0083] Example 2

[0084] As shown in Figures 6, 7, and 8, the outer sleeve includes a support sleeve 73 connected to the wrench body 61. One end of the support sleeve 73, away from the wrench body 61, is connected to an outer end sleeve 74. The end face of the outer end sleeve 74 can press against the un-grooved annular surface 13 of the first countersunk head 12. A hollow gun head 75, capable of axial movement, is inserted within the support sleeve 73.

[0085] Further, as shown in Figures 6 and 7, the wrench clamping structure includes a wrench head 81 that can be sleeved on the core rod head 25. The wrench head 81 is connected to the torque output part 62 via a drive connecting rod 83. The wrench head 81 and the drive connecting rod 83 are rotatably disposed within the gun head 75. A rotor sleeve 84 that can rotate with the core rod part 2 is sleeved on the outside of the wrench head 81. A thrust bearing 85 is disposed between the rotor sleeve 84 and the support sleeve 73. The end of the rotor sleeve 84 away from the torque output part 62 can be locked into the necking groove part 24. The axial pulling part includes a stepped surface disposed on the rotor sleeve 84 that can axially abut against the annular bearing plane 251.

[0086] Before the installation tool is activated, the support sleeve 73 and the outer end sleeve 74 are connected by threads. The support sleeve 73 is connected to the wrench body 61, and a suitable positive pressure is applied to the non-grooved annular surface 13 to ensure that the nail body 1 does not rotate. The outer end sleeve 74 presses against the non-grooved annular surface 13 of the nail body 1, and the core rod head 25 is fitted into the rotor sleeve 84. At this time, the outer end sleeve 74 is rotated. Due to the thread action between the support sleeve 73 and the outer end sleeve 74, the support sleeve 73 moves backward relative to the outer end sleeve 74, transmitting pressure to the thrust bearing 85. The thrust bearing 85 presses the rotor sleeve 84 backward until the stepped surface of the rotor sleeve 84 axially abuts against the annular bearing plane 251, pulling the core rod 2 backward. This creates a gap of about 0.1 mm between the second countersunk head 22 of the core rod 2 and the countersunk hole 15 of the nail body 1, reducing the contact between the core rod 2 and the nail body 1, thereby reducing the friction force on the core rod 2 during installation. Push the gun head 75, and the core rod head 25 is inserted into the wrench head 81.

[0087] The torque output part 62 rotates, the nail sleeve part 3 gradually deforms, and when the nail sleeve part 3 is formed to a sufficiently large size, the neck groove part 24 is twisted off, and the single-sided connecting bolt 100 is installed.

[0088] To improve the clamping stability of the outer sleeve on the nail sleeve 3 and increase the friction between the installation tool and the non-tightening groove annular surface 13, the abutting end face of the outer sleeve and the nail sleeve 3 can be roughened. The roughness of the end face of the outer sleeve 74 is greater than or equal to Ra12.5.

[0089] Example 3

[0090] The method of installing the single-sided connecting bolt 100 disclosed herein using the aforementioned single-sided connecting bolt installation tool 200 differs from the prior art in that it does not require wrench slot installation. Instead, the installation tool applies positive pressure to the nail body 1, and the wrench clamping structure simultaneously pulls the core rod 2 outward, reducing the friction between the second countersunk head 22 of the core rod 2 and the nail body 1, thereby ensuring that the nail body does not rotate.

[0091] The installation method includes: assembling the single-sided connecting bolt 100 through-hole onto the part to be connected; applying pressure to the non-tightening groove annular surface 13 of the first countersunk head 12 on the bolt body 1 through the outer sleeve of the single-sided connecting bolt installation tool 200; simultaneously applying a pulling force to the core rod 2 away from the bolt body 1 through the tightening clamping structure, thus fixing the bolt body 1 in place. The torque output part 62 drives the core rod 2 to rotate through the tightening clamping structure, tightening the connecting nut part 4, and simultaneously pushing the bolt sleeve part 3 to deform and press against the surface of the part to be connected, completing the installation of the single-sided connecting bolt 100. The state of the installation process is shown in Figure 10.

[0092] Specifically, the single-sided connecting bolt 100 is assembled onto the part to be connected by passing it through, including: installing the bolt body 1 into the mounting hole on the part to be connected (interlayer 9), and assembling the core rod 2, the bolt sleeve 3, and the nut 4.

[0093] As shown in Figures 9a, 9b, 9c, and 9d, the stress conditions during the installation of single-sided connecting bolts specifically include the following states.

[0094] In the initial installation state, as shown in Figure 9a, the installation tool is activated. To prevent the nail body 1 from rotating, it is initially necessary to overcome the tightening force after the core rod 2 and nut 4 are tightened. This tightening force is the frictional force between the conical anti-slip groove 16 of the nail body and the nail sleeve 3 = coefficient of friction (contact surface roughness) × pressure (contact surface pressure).

[0095] During installation, as shown in Figure 9b, before the nail sleeve 3 contacts the part to be connected (interlayer 9), the installation tool first applies a pulling force F1 to the neck groove 24 of the core rod 2 to reduce the friction between the second countersunk head 22 of the core rod 2 and the nail body 1. During installation, before the nail sleeve 3 contacts the side of the interlayer 9, as the nail sleeve 3 begins to deform, the force F4 of the nut 4 pushing the nail sleeve 3 to deform gradually increases, the friction between the nail sleeve 3 and the nail body 1 gradually increases, the normal force F2 applied by the core rod 2 to the nail body 1 gradually increases, and the force that drives the nail body 1 to rotate increases accordingly. Therefore, the normal force F3 required to press the nail body 1 to fix it also gradually increases.

[0096] During installation, as shown in Figure 9c, after the nail sleeve 3 is clamped to the interlayer 9, and the nail sleeve 3 is formed and comes into contact with the interlayer 9, the clamping force F5 of the nail sleeve 3 on the interlayer 9 gradually increases. The friction between the nail sleeve 3 and the side of the interlayer 9 also increases, preventing the nail body 1 from rotating. Therefore, the positive pressure F3 required to press the nail body 1 to fix it gradually decreases.

[0097] In the later stages of installation, as shown in Figure 9d, when the frictional force between the forming surface of the nail sleeve 3 and the side of the interlayer is equal to the frictional force between the core rod 2 and the nail body 1 (countersunk surface, threaded pair, and nail anti-slip groove), the required positive pressure F3 is zero. Therefore, the positive pressure F3 required to press the end face of the nail body 1 (the ring surface 13 without the wrench groove) is a process of first increasing and then decreasing.

[0098] Throughout the installation process, the pressure is transferred to the end face of the nail body 1 through the installation tool, which keeps the nail body 1 stationary during installation. The installation tool puts tension on the core rod 2, while reducing the friction between the countersunk holes of the nail body 1 and the core rod 2. This helps to reduce molding resistance, improve installation stability and reliability, and ensure the smooth completion of the installation process.

[0099] Example 4

[0100] The installation method of the single-sided connecting bolt disclosed herein using a conventional installation gun includes: fixing the bolt body 1 to the mounting hole on the part to be connected (interlayer 9) by adhesive bonding or interference connection; inserting the core rod 2 from the first countersunk head 12 of the bolt body 1 to the other end; sequentially setting the bolt sleeve 3 (with the ring 5 already installed) and the nut 4 at the other end of the bolt body 1; threading the core rod 2 through the bolt body 1, the ring 5, and the bolt sleeve 3 to the nut 4; and rotating the core rod 2 with an installation gun (any existing installation gun will suffice, without the need for the aforementioned single-sided connecting bolt installation tool 200) to drive the nut 4 and the bolt sleeve 3 to move towards the part to be connected (interlayer 9) and tighten them.

[0101] Specifically, the adhesive bonding method of the nail body 1 includes: applying adhesive to the outer wall surfaces of the first smooth rod body 11 and the first countersunk head 12, and bonding the nail body 1 to the mounting hole (aircraft skin mounting hole) on the part to be connected (interlayer 9) to ensure that the nail body 1 does not rotate during the installation process.

[0102] The interference connection method of the nail body 1 includes: using the first smooth rod body 11 to interfere with the mounting hole (aircraft skin mounting hole) on the part to be connected (interlayer 9), the interference between the mounting hole and the first smooth rod body 11 is between 0.02-0.05mm, to ensure that the nail body 1 does not rotate during the installation process.

[0103] As described above, the single-sided connecting bolt and its installation tool disclosed herein have the following beneficial effects: Unlike the single-sided connecting bolts of the prior art, the present disclosure removes the four wrench grooves on the end face of the bolt body, making it a grooveless single-sided connecting bolt. The end face of the first countersunk head is set as a grooveless annular surface, resulting in a smooth cross-section after installation and improved fatigue and tensile properties. After installation, the overall fuselage is smoother, improving the aerodynamic performance of the aircraft.

[0104] The neck groove of the core rod disclosed herein adopts a special design. An annular bearing plane is provided on the end face of the core rod head near the neck groove. The neck groove can withstand greater tensile force, which allows the core rod to be lifted during installation and reduces the friction between the core rod and the nail body.

[0105] When using the installation tool disclosed herein to install a single-sided connecting bolt, the friction coefficient between the installation tool and the end face of the bolt body is increased throughout the installation process. The installation tool presses the end face of the bolt body to keep it stationary during installation. The installation tool also applies tension to the core rod, reducing the friction between the countersunk hole of the bolt body and the core rod. This helps to reduce forming resistance, improve installation stability and reliability, and ensure the smooth completion of the installation process.

[0106] The above description is merely an illustrative embodiment of this disclosure and is not intended to limit the scope of this disclosure. Any equivalent changes and modifications made by those skilled in the art without departing from the concept and principles of this disclosure should fall within the scope of protection of this disclosure.

Claims

1. A single-sided connection bolt, wherein, include: A nail body portion is fixedly inserted into the component to be connected. The nail body portion includes a first smooth rod body, a first countersunk head is provided at the first end of the first smooth rod body, and the end face of the first countersunk head is a ring surface without a wrench groove. A nail body center hole is provided axially in the first smooth rod body, and a countersunk hole is provided in the first countersunk head. The core rod portion includes a second smooth rod body that passes through the central hole of the nail body. A second countersunk head corresponding to the countersunk hole is provided at the first end of the second smooth rod body, and an external thread portion is provided at the second end of the second smooth rod body. The second countersunk head is connected to the core rod head through a necking groove. An annular tensile-bearing plane is provided on the end face of the core rod head near the necking groove to increase the load-bearing area between the installation tool and the core rod head. The nail sleeve portion has a first end that can move inward from the second end of the first optical rod body and can radially deform to abut against the member to be connected; as well as The nut portion is abutted against the second end of the nail sleeve portion; the external thread portion passes through the nail sleeve portion and is threadedly connected to the nut portion; the core rod portion rotates to drive the nut portion to move towards the nail body portion for tightening, and the nut portion pushes the nail sleeve portion to move and deform; a locking structure is provided on the nut portion.

2. The single-sided connecting bolt as described in claim 1, wherein, A ring is fitted inside the first end of the nail sleeve, and the ring can abut against the part to be connected as the first end of the nail sleeve deforms.

3. The single-sided connecting bolt as described in claim 2, wherein, A tapered anti-slip groove with a gradually decreasing diameter is provided at the second end of the first optical rod body. The tapered anti-slip groove is used for guiding the movement of the first end of the nail sleeve and for radial extrusion deformation.

4. The single-sided connecting bolt as described in claim 1, wherein, A first anti-slip tooth is provided on the end face of the second end of the nail sleeve portion, and a second anti-slip tooth is provided on the end face of the nut portion near the nail sleeve portion, which can engage with the top of the first anti-slip tooth.

5. The single-sided connecting bolt as described in claim 1, wherein, The locking structure includes at least one locking recess structure disposed on the side wall of the nut portion, the radial inner end of the locking recess structure being disposed in such a way that it protrudes from the internal thread portion of the nut portion, and the locking recess structure is used to lock the external thread portion of the core rod portion.

6. The single-sided connecting bolt as described in claim 1, wherein, The surface roughness of the first sinker head is greater than or equal to Ra6.

3.

7. The single-sided connecting bolt as described in claim 1, wherein, The nail body is made of titanium alloy.

8. A single-sided bolt attaching tool as claimed in any one of claims 1 to 7, wherein, include: A torque wrench includes a wrench body, wherein the wrench body is provided with a torque output section; as well as A working sleeve is detachably connected to the torque wrench. The working sleeve includes an outer sleeve, the first end of which is fixedly connected to the wrench body, and the end face of the second end of which can press against the non-grooving annular surface of the first countersunk head. A wrench clamping structure for rotating and transmitting torque is provided inside the outer sleeve. The first end of the wrench clamping structure is fixedly connected to the torque output part, and the second end of the wrench clamping structure can be sleeved on the core rod head. An axial pulling part is provided at the second end of the wrench clamping structure, which can axially press against the annular bearing plane and pull the core rod head towards the torque output part.

9. The installation tool for the single-sided connecting bolt as described in claim 8, wherein, The outer sleeve includes a fixed sleeve connected to the wrench body. A movable sleeve is circumferentially fixed and axially movable along the fixed sleeve at the end of the fixed sleeve away from the wrench body. The end face of the movable sleeve away from the fixed sleeve can press against the untightened groove annular surface of the first countersunk head.

10. The installation tool for the single-sided connecting bolt as described in claim 9, wherein, The wrench clamping structure includes a wrench head that can be sleeved on the head of the core rod, the wrench head being connected to the torque output part via a torque transmission shaft; a radially elastically deformable jaw chuck is provided at the end of the wrench head away from the torque transmission shaft, the jaw chuck being able to radially retract and clamp the broken neck groove; a radially reduced locking step is provided at the end of the jaw chuck away from the torque transmission shaft, the locking step forming the axial pulling part, the locking step being able to abut against the annular bearing plane; an external thread is provided on the outer wall of the torque transmission shaft, and an internal thread is provided on the inner wall of the movable sleeve, the torque transmission shaft and the movable sleeve forming a screw-nut structure, the rotation of the torque transmission shaft being able to be converted into axial movement of the movable sleeve.

11. The installation tool for the single-sided connecting bolt as described in claim 9, wherein, A guide key is provided on the inner wall of the fixed sleeve, and a guide groove is provided on the outer wall of the movable sleeve, which can be slidably fitted onto the guide key.

12. The installation tool for the single-sided connecting bolt as described in claim 9, wherein, The roughness of the end face of the movable sleeve away from the fixed sleeve is greater than or equal to Ra12.

5.

13. The installation tool for the single-sided connecting bolt as described in claim 8, wherein, The outer sleeve includes a support sleeve connected to the wrench body. One end of the support sleeve away from the wrench body is connected to an outer end sleeve. The end face of the outer end sleeve can press against the untightened groove annular surface of the first countersunk head. A hollow gun head that can move axially is inserted into the support sleeve.

14. The installation tool for the single-sided connecting bolt as described in claim 13, wherein, The wrench clamping structure includes a wrench head that can be sleeved on the head of the core rod, and the wrench head is connected to the torque output part through a drive connecting rod; the wrench head and the drive connecting rod are rotatably disposed inside the gun head; a rotor sleeve that can rotate with the core rod is sleeved on the outside of the wrench head, and a thrust bearing is disposed between the rotor sleeve and the support sleeve; the end of the rotor sleeve away from the torque output part can be locked into the necking groove, and the axial pulling part includes a stepped surface disposed on the rotor sleeve and capable of axially abutting against the annular bearing plane.

15. The installation tool for the single-sided connecting bolt as described in claim 13, wherein, The roughness of the end face of the outer end sleeve is greater than or equal to Ra12.

5.

16. A method of installing a single-sided connector bolt as claimed in any one of claims 1 to 7, wherein, include: The nail body is fixedly connected to the mounting hole on the part to be connected by adhesive bonding or interference connection. The core rod is inserted from the first countersunk head of the nail body to the other end. The nail sleeve and the nut are arranged in sequence at the other end of the nail body. After the core rod passes through the nail body and the nail sleeve, it is threadedly connected to the nut. By rotating the core rod, the nut and the nail sleeve are driven to move towards the part to be connected and tightened.

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