Super bolt and nut for gravity support

Abstract

The invention belongs to the technical field of fasteners, and discloses a super bolt nut for gravity supporting, which comprises a double-end stud, the two ends of the double-end stud are respectively sleeved with a nut and a pretensioner in a threaded manner, and the outer surface of the double-end stud is movably sleeved with a hardened gasket close to one end of the pretensioner. Pushing screws are evenly connected into the pre-tightener in a threaded and sleeved mode, a pushing block is installed at the end, close to the hardened gasket, of the end of each pushing screw, and the end face, close to the hardened gasket, of the nut is provided with an arc face. By means of the innovative design of the internal threads of the elastic nut, efficient force transmission and uniform stress distribution are achieved, the pressure between the threads is reduced, the thread seizure risk is reduced, the service life of the bolt is prolonged, particularly, the stress distribution is optimal at the inclination angle of 6 degrees, and the structural stability and safety are improved; and the cambered surface deforms when being stressed, so that the contact is more sufficient.

Description

Technical Field

[0001] The invention belongs to the technical field of fasteners, and in particular relates to a super bolt and nut for gravity support. Background Art

[0002] When a traditional bolt is subjected to force, the internal thread design may lack sufficient deformation coefficient, resulting in the inability to effectively transmit force to the next level of thread. This may cause some threads to be overstressed while other threads are understressed, thereby reducing the overall force transmission efficiency. When the bolt is subjected to uneven force, some threads may be subjected to excessive stress and become stress concentration points. These areas are more prone to fatigue failure, resulting in premature failure of the bolt. Uneven force may lead to uneven pressure distribution between threads, and some threads may be subjected to excessive pressure, increasing the risk of thread seizure. This will not only affect the removal and replacement of the bolt, but may also cause damage to the equipment and system; when subjected to high loads, bolts subjected to uneven force may break or fail due to excessive local stress, thereby threatening the structural stability and safety of the equipment and system. Bolt failure and damage caused by uneven force may require more frequent maintenance and replacement. This not only increases maintenance costs, but may also affect the normal operation and production efficiency of the equipment. Therefore, it is necessary to design a gravity-supported super bolt with uniform force. Summary of the invention

[0003] The object of the present invention is to provide a super bolt and nut for gravity support to solve the problems raised in the above background technology.

[0004] In order to achieve the above-mentioned purpose, the present invention provides the following technical scheme: a super bolt nut for gravity support, comprising a stud, wherein both ends of the stud are respectively threadedly sleeved with a nut and a preloader, a hardened washer close to one end of the preloader is movably sleeved on the outer surface of the stud, a push screw is evenly threadedly sleeved on the inside of the preloader, a push block is installed at the end of the push screw close to one end of the hardened washer, and an arc surface is provided on the end face of the nut close to the hardened washer.

[0005] Preferably, an inclined block is evenly and fixedly mounted on the inner wall of the nut, a protrusion is provided at the bottom end of the inclined block, and a fastening sleeve located inside the nut is threadedly sleeved on the outer surface of the stud.

[0006] Preferably, one end of the fastening sleeve and the inclined surface of the inclined block are on an inclined surface with the same slope, and their contact surfaces are in parallel contact with each other.

[0007] Preferably, the protrusion is made of rubber asphalt material, which is deformed after being squeezed and fits tightly with the thread of the end of the stud.

[0008] Preferably, the arc surface will slightly deform when subjected to force, ensuring uniform force.

[0009] Preferably, the nut is an elastic nut with a settlement value of 0.24 mm. When the angle of the nut is 6°, the stress difference is the smallest, the maximum stress is also the smallest, and the force is more uniform.

[0010] Preferably, the deformation coefficient of the internal thread of the nut is higher than that of the external thread, and the elastic deformation of the thread can better transmit the force to the next-level thread, making the force distribution more uniform.

[0011] Preferably, the thread tolerance grade of the nut is 6g-6H, 2A-2B.

[0012] Preferably, the hardness of the hardened washer is selected to be within the range of greater than the hardness of the nut and less than the hardness of the stud.

[0013] Preferably, the inclined blocks and the protruding blocks form a group, and there are ten groups evenly distributed on the inner wall of the nut.

[0014] The beneficial effects of the present invention are as follows:

[0015] 1. The present invention has a higher deformation coefficient through the internal thread design of the elastic nut, which can more effectively transmit force to the next-level thread compared to traditional bolts. The elastic deformation between the threads not only ensures the uniform distribution of force and avoids the problem of excessive force on the single-level thread, but also significantly reduces the pressure between the threads, thereby reducing the risk of thread seizure and extending the service life of the bolt.

[0016] 2. The present invention uses the design of the elastic nut to make its settlement value lower when subjected to stress, and the overall tendency to shrink inwards is present, which helps to distribute the stress more evenly to each thread. In particular, when the elastic nut reaches a 6° inclination angle, the stress difference reaches the minimum, and the maximum stress is also reduced to the minimum, which further proves the excellent performance of the new bolt in terms of force uniformity, the stress on the intermediate workpiece reaches the design conditions and the contact surface is uniformly stressed.

[0017] 3. The invention designs each thread to bear force more evenly, and the new bolt has higher structural stability and safety when subjected to high loads. This means that under extreme conditions, the new bolt is less likely to break or fail, thereby ensuring the reliable operation of equipment and systems. Since the new bolt has a longer service life and a lower failure rate, the maintenance cost of the equipment can be reduced. In addition, since the pressure between the threads is reduced, the risk of thread seizure is reduced, which also makes the removal and replacement of the bolt easier and faster. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0019] Figure 2It is a partial cross-sectional schematic diagram of the present invention;

[0020] Figure 3 For the present invention Figure 2 A partial enlarged view of the middle part;

[0021] Figure 4 An exploded view of the fastening sleeve and the nut of the present invention;

[0022] Figure 5 For the present invention Figure 4 A partial enlarged view of point B in the middle;

[0023] Figure 6 It is a schematic diagram of the structure of the pretensioner of the present invention;

[0024] Figure 7 It is a schematic diagram of the cross-sectional structure of the nut of the present invention;

[0025] Figure 8 This is a diagram of thread deformation caused by various reasons in the present invention;

[0026] Fig. 9 A comparison diagram of thread elastic deformation coefficient values ​​caused by various reasons in the present invention;

[0027] Fig.10 is the stress distribution diagram of the present invention;

[0028] Fig.11 It is the sedimentation analysis diagram of the present invention;

[0029] Fig.12 The stress analysis of the thread of the present invention Figure 1 ;

[0030] Fig.13 The stress analysis of the thread of the present invention Figure 2 ;

[0031] Fig.14 This is a data table of stress analysis at the thread of the present invention.

[0032] In the figure: 1. stud; 2. nut; 3. preloader; 4. hardened washer; 5. push screw; 6. push block; 7. inclined block; 8. protrusion; 9. fastening sleeve; 10. arc surface. DETAILED DESCRIPTION

[0033] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] like Figures 1 to 14 As shown, an embodiment of the present invention provides a super bolt nut for gravity support, including a stud 1, two ends of the stud 1 are respectively threadedly sleeved with a nut 2 and a preloader 3, the outer surface of the stud 1 is movably sleeved with a hardened washer 4 close to one end of the preloader 3, the inner part of the preloader 3 is evenly threadedly sleeved with a push screw 5, the end of the push screw 5 is installed with a push block 6 close to one end of the hardened washer 4, and the end face of the nut 2 close to the hardened washer 4 is provided with an arc surface 10.

[0035] When in use, the part to be fixed is inserted between the nut 2 and the hardened washer 4, and the nut 2 is rotated to seal one end of the stud 1, and then the preloader 3 is threadedly sleeved on. The push screw 5 is rotated to drive the push block 6 to move close to the hardened washer 4, so that the hardened washer 4 fits tightly against the part to be fixed. When under pressure, the arc surface 10 on the nut 2 will be deformed.

[0036] The inner wall of the nut 2 is evenly fixed with an inclined block 7 , the bottom end of the inclined block 7 is provided with a protrusion 8 , and the outer surface of the stud 1 is threadedly sleeved with a fastening sleeve 9 located inside the nut 2 .

[0037] After the position of the nut 2 is determined, the fastening sleeve 9 is put on the stud 1, and the bevel block 7 is squeezed by the fastening sleeve 9, so that the protrusion 8 is in close contact with the thread on the surface of the stud 1 to prevent the nut 2 from rotating accidentally.

[0038] One end of the fastening sleeve 9 and the inclined surface of the inclined block 7 are on an inclined surface with the same slope, and their contact surfaces are parallel to each other.

[0039] The protrusion 8 is made of rubber asphalt material, which is deformed after being squeezed and fits tightly with the thread at the end of the stud 1.

[0040] The arc surface 10 will slightly deform when subjected to force, ensuring uniform force.

[0041] Among them, nut 2 is an elastic nut with a settlement value of 0.24 mm. When the angle of nut 2 is 6°, the stress difference is the smallest, the maximum stress is also the smallest, and the force is more uniform.

[0042] Among them, the deformation coefficient of the internal thread of nut 2 is higher than that of the external thread, and the elastic deformation of the thread better transmits the force to the next level of thread, making the force distribution more uniform.

[0043] Among them, the thread tolerance grade of nut 2 is 6g-6H, 2A-2B.

[0044] The hardness of the hardened washer 4 is preferably selected to be greater than the hardness of the nut 2 and less than the hardness of the stud 1 .

[0045] The inclined blocks 7 and the protruding blocks 8 form a group, and there are ten groups evenly distributed on the inner wall of the nut 2 .

[0046] Experimental verification:

[0047] Nut 2 calculation sheet:

[0048] Calculation: Double-ended stud 1 thread specification: M30x2

[0049] Minimum tensile strength Rm: 1230 (MPa)

[0050] Minimum yield strength Rpo.2: 1034 (Mpa)

[0051] Guaranteed load formula: F = A*Rm (1)

[0052]

[0053] d 2 : Middle diameter

[0054] d 3 : Trail

[0055] For the calculation formula of thread size, see GB / T196

[0056] Stress cross-sectional area: A = 621 mm 2

[0057] Guaranteed load: F = 763KN

[0058] Combined with GB / T3098.1, it can be known that the stud can withstand a load of 758KN.

[0059] Nut thread specification: 7 / 16-20-UNF; M30X2

[0060] The load-bearing capacity refers to the data of GB / T3098.2 Mechanical Strength of Fasteners - Nuts. The 7 / 16-20-UNF and M30X2 internal threads ensure that the load meets the use requirements.

[0061] Push screw specification: 7 / 16-20-UNF

[0062] According to test data, the nut provides a pre-tightening force of 350KN to 540KN, which can meet the use requirements.

[0063] Preload force:>35KN

[0064] Corresponding preload total FB:> 350KN

[0065] Torque formula:

[0066]

[0067] P: Pitch

[0068] Hg: Thread friction coefficient (0.18)

[0069] k: contact surface friction coefficient (0.18)

[0070] D km : Contact surface force diameter: 8.6mm

[0071] Recommended torque calculated by (3): 90 (Nm) ~ 118 (Nm)

[0072] Torque tolerance ±10%.

[0073] Push screw calibration:

[0074] Safety factor: 0.7

[0075] Preload force: 65KN

[0076] The friction coefficient and formula that meet the use requirements refer to VDI2230 High Strength Bolt Connection System

[0077] Statistical Computing.

[0078] Number of screws: 10

[0079] Total preload force FB:>350KN.

[0080] according to Figure 8 and Fig. 9 :It can be seen that the deformation coefficient of the internal thread is higher than that of the external thread. The elastic deformation of the thread can better transmit the force to the next level of thread, thereby ensuring a more even force distribution and avoiding excessive force on a single level of thread. At the same time, it can reduce the pressure between threads, improve the force situation, reduce the risk of thread seizure, and increase the life of the thread.

[0081] in conclusion:

[0082] Based on the above calculations:

[0083] Screw yield ≥1200Mpa;

[0084] Stud yield ≥1034Mpa;

[0085] Nut body guaranteed load:

[0086] Refer to the data of GB / T3098.2 Mechanical Strength of Fasteners - Nuts, 7 / 16-20-UNF and M30X2 internal threads ensure that the load meets the use requirements.

[0087] Thread tolerance grade: 6g-6H, 2A-2B;

[0088] According to "Threaded Connection Theory and Calculation", the screwing length is: >4.8mm at the screw and >18mm at the stud. This can meet the use requirements.

[0089] In order to protect the screws and reduce the influence of gasket deformation on the elastic deformation of nut thread, the gasket hardness should be selected to be greater than the hardness range of the nut and less than the hardness range of the screw.

[0090] According to the instruction manual Fig.11 It can be seen that the settlement value of the clamping part in the hexagonal nut assembly is 1.30mm, while the settlement value of the clamping part in the elastic nut assembly is 0.24mm, and the settlement value of the elastic nut is lower. The clamping part as a whole tends to shrink inward.

[0091] According to the instruction manual Fig.12 It can be seen that the local maximum stress at the first three threads of the hexagonal nut assembly is 156.4Mpa (the last three threads are 11.4Mpa), and the local maximum stress at the first three threads of the elastic nut assembly is 154.9Mpa (the last three threads are 43.9Mpa). Although the stress values ​​of the first three threads are not much different, the stress difference of the last three threads is larger. The last three threads of the elastic nut distribute more stress, making each thread more evenly stressed.

[0092] Materials: Inconel 718

[0093] According to the instruction manual Fig.13 It can be seen that the elastic telescopic nut (6°) slightly reduces the maximum stress of the head meshing teeth and increases the maximum stress of the bottom meshing teeth compared to the elastic telescopic nut (3°), further reducing the stress difference. The elastic telescopic nut (10°) has an increase in the maximum stress of the head meshing teeth compared to the elastic telescopic nut (6), and the maximum stress at the bottom is also slightly reduced.

[0094] According to the instruction manual Fig.14 It can be seen that when the elastic nut is 6°, the stress difference is the smallest, and the maximum stress is also the smallest, indicating that the force is more uniform than at other angles.

[0095] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0096] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A super bolt and nut for gravity support, comprising a stud (1), characterized in that: The two ends of the stud bolt (1) are respectively threadedly sleeved with a nut (2) and a preload (3); the outer surface of the stud bolt (1) is movably sleeved with a hardened washer (4) close to one end of the preload (3); the interior of the preload (3) is evenly threadedly sleeved with a thrust screw (5); the end of the thrust screw (5) close to one end of the hardened washer (4) is provided with a thrust block (6); the end surface of the nut (2) close to the hardened washer (4) is provided with an arc surface (10).

2. A super bolt and nut for gravity support according to claim 1, characterized in that: The inner wall of the nut (2) is evenly fixed with an inclined block (7), the bottom end of the inclined block (7) is provided with a protrusion (8), and the outer surface of the stud (1) is threadedly sleeved with a fastening sleeve (9) located inside the nut (2).

3. A super bolt and nut for gravity support according to claim 2, characterized in that: One end of the fastening sleeve (9) is on an inclined surface with the same slope as the inclined surface of the inclined block (7), and their contact surfaces are parallel to each other.

4. The super bolt and nut for gravity support according to claim 2, characterized in that: The protrusion (8) is made of rubber asphalt material and deforms after being squeezed, so as to fit tightly with the thread at the end of the stud (1).

5. The super bolt and nut for gravity support according to claim 1, characterized in that: The arc surface (10) will slightly deform when subjected to force, thereby ensuring uniform force.

6. The super bolt and nut for gravity support according to claim 1, characterized in that: The nut (2) is an elastic nut with a settlement value of 0.24 mm. When the angle of the nut (2) is 6°, the stress difference is the smallest, and the maximum stress is also the smallest, and the force is more uniform.

7. The super bolt and nut for gravity support according to claim 1, characterized in that: The deformation coefficient of the internal thread of the nut (2) is higher than that of the external thread, and the thread undergoes elastic deformation to better transmit force to the next-level thread, making the force distribution more uniform.

8. The super bolt and nut for gravity support according to claim 1, characterized in that: The thread tolerance grade of the nut (2) is 6g-6H, 2A-2B.

9. The super bolt and nut for gravity support according to claim 1, characterized in that: The hardness of the hardened washer (4) is preferably selected within a range of hardness greater than that of the nut (2) and less than that of the stud (1).

10. The super bolt and nut for gravity support according to claim 2, characterized in that: The inclined blocks (7) and the protruding blocks (8) form a group, and there are ten groups in total, which are evenly distributed on the inner wall of the nut (2).

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