Self-locking type double-thread check bolt

Abstract

The invention relates to the technical field of fasteners, in particular to a self-locking type double-thread lock bolt which comprises bolts and a main nut, and the main nut is located between the bolts and is in coaxial threaded connection with the bolts; through the arrangement of the auxiliary screw rod and the auxiliary nut, due to the fact that the rotation directions of the main nut and the auxiliary nut are opposite, and the auxiliary nut drives the first gasket to rotate in the same direction, opposite friction force is generated between the main nut and the first gasket, and then the problem that the main nut is loosened is avoided; furthermore, a tension spring is arranged at the rear end of the auxiliary nut, the auxiliary nut rotates towards the rear end due to vibration, the tension spring applies forward pressure to the auxiliary nut, the auxiliary nut cannot rotate and move towards the rear end, looseness of the auxiliary nut is avoided, and therefore it is guaranteed that the main nut cannot be loosened, and then it is guaranteed that the bolt cannot be loosened.

Description

Technical Field

[0001] The present invention relates to the technical field of fasteners, in particular to a self-locking double-threaded anti-loosening bolt. Background Art

[0002] Self-locking double-threaded anti-loosening bolts are specially designed with structural innovation and material optimization to systematically solve the loosening problem of traditional bolts under vibration, temperature difference and alternating loads. Self-locking double-threaded anti-loosening bolts are mainly used in key basic parts in high-end manufacturing, energy equipment, transportation and other fields. For mining machinery and equipment with high vibration frequencies, mining machinery usually produces strong vibrations during operation, which will cause the bolts to be subjected to periodic alternating stress, resulting in bolt loosening. For example, during the operation of the ore conveyor belt, impacts will be generated due to the loading and unloading of materials and the starting and stopping of the conveyor belt. Especially when the ore on the conveyor belt is unevenly distributed or encounters larger pieces of ore, the impact force will be more obvious, causing the bolts fixing the conveyor belt bracket, roller and other components to be impacted, resulting in bolt loosening.

[0003] In response to the above problems, the prior art has proposed some solutions. For example, patent application number: CN202210616070.4 discloses a self-installing anti-loosening bolt fastener with double threads. This solution symmetrically opens a group of strip grooves that cooperate with the locking wedge on the surface of the screw, and respectively arranges a first internal thread and a second internal thread with two different inclination angles on the inner side of the fastening nut, and arranges an annular groove that fits the locking wedge on the top surface of the fastening nut. The fastening nut is fixed to the screw by the first internal thread cooperating with the first external thread on the surface of the screw, and the second internal thread cooperates with the second external thread at the locking end of the bottom of the locking wedge to further lock the fastening nut on the screw. In addition, a limiting gasket with a limiting card is provided on the screw to guide the locking end at the bottom of the locking wedge, and the limiting card can The second external thread at the locking end of the locking wedge bottom is engaged with the second internal thread on the inner side of the fastening nut, and the fastening nut is locked on the screw rod through two sets of locking wedges. Compared with ordinary nuts, the fastening nut has a locking function to prevent the nut from loosening from the bolt, thereby improving the reliability and safety of the bolt and nut connection of vibrating electrical equipment, high-altitude hardware or transmission lines, ensuring equipment safety and personal safety, and saving a lot of financial and material resources in the operation and maintenance work. The fastener has a simple and reliable structure, is easy to operate and use, has a good locking effect, and is highly practical. Although the above scheme solves the problem of loosening of vibration bolts and nuts generated by the equipment during operation, the above technical scheme opens a strip groove on the bolt. The setting of the strip groove reduces the shear resistance of the bolt, and under the action of alternating loads, the risk of bolt breakage and failure is prone to occur. Summary of the Invention

[0004] The purpose of the present invention is to provide a self-locking double-threaded anti-loosening bolt to solve the problem raised in the above background technology that in some mining machinery and equipment with high vibration frequencies, during operation, the loading and unloading of materials and the starting and stopping of conveyor belts generate impacts, especially when the ore distribution on the conveyor belt is uneven or encounters large pieces of ore, strong vibrations will be generated, causing the bolts to be subjected to periodic alternating stress and impact loads, resulting in bolt loosening, while solving the shortcomings of the existing technology.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A self-locking double-threaded anti-loosening bolt, comprising a bolt and a main nut, wherein the main nut is coaxially threadedly connected to the bolt, and is characterized in that a secondary screw is coaxially arranged on the end face of the bolt away from the bolt head, the diameter of the secondary screw is smaller than the diameter of the bolt, and the thread direction is opposite to that of the bolt, the secondary screw is coaxially threadedly connected to the secondary nut, and a plurality of limiting holes are provided on the outer end face of the secondary nut, the axis center lines of the plurality of limiting holes are parallel to the axis center line of the bolt, and are uniformly distributed along the circumference of the axis of the secondary nut, the plurality of limiting holes are slidably connected to the limiting rods, and multiple A No. 1 washer is fixedly installed on the end of the limiting rod close to the main nut, and the end of the No. 1 washer away from the limiting rod is connected to the main nut. A tension spring, a No. 3 washer and a fixing nut are coaxially arranged on the end of the limiting rod away from the main nut. The fixing nut is threadedly connected to the limiting rod, and the two ends of the tension spring are respectively fixedly connected to the secondary nut and the No. 3 washer. The two ends of the No. 3 washer are respectively fixedly connected to the tension spring and the fixing nut. Fixing holes are provided on the side walls of the fixing nut and the limiting rod, and a No. 2 cotter pin is coaxially inserted in the fixing hole.

[0007] By setting the secondary screw and the secondary nut, the thread direction of the secondary screw is opposite to that of the bolt, and thus the rotation directions of the main nut and the secondary nut are opposite. When the main nut and the secondary nut begin to rotate and loosen due to vibration, since the rotation directions of the main nut and the secondary nut are opposite, the secondary nut drives the No. 1 washer to rotate in the same direction, so opposite friction forces are generated between the main nut and the No. 1 washer, thereby avoiding the problem of loosening of the main nut; further, a tension spring is set at the rear end of the secondary nut, and the secondary nut rotates toward the rear end due to vibration, and the tension spring applies a front pressure to the secondary nut, so that the secondary nut cannot rotate in the loosening direction, thereby avoiding loosening of the secondary nut, thereby ensuring that the main nut will not loosen, and thus ensuring that the bolt will not loosen.

[0008] Preferably, a No. 2 washer is provided between the No. 1 washer and the main nut, and the end of the No. 2 washer away from the secondary nut is connected to the main nut. The end of the No. 1 washer away from the secondary nut is provided with a plurality of No. 1 serrations, and the plurality of No. 1 serrations are arrayed along the circumference of the axis of the No. 1 washer, and the direction of the No. 1 serrations is opposite to the direction in which the secondary nut is screwed in. The end of the No. 2 washer away from the bolt head is provided with a plurality of No. 2 serrations, and the plurality of No. 2 serrations are arrayed along the circumference of the axis of the No. 2 washer, and the direction of the No. 2 serrations is the same as the direction in which the secondary nut is screwed in. The No. 1 serrations and the No. 2 serrations are engaged with each other.

[0009] By providing No. 1 serrations and No. 2 serrations on the mutual friction surfaces of No. 1 washer and No. 2 washer respectively, when the main nut becomes loose due to vibration and impact, No. 2 washer rotates in the loosening direction following the main nut. Since the direction of No. 1 serrations on No. 1 washer is opposite to the direction of No. 2 serrations on No. 2 washer, the main nut is prevented from rotating in the loosening direction, thereby ensuring that the bolt will not loosen.

[0010] Preferably, multiple limit grooves are provided on the inner side walls of multiple limit rods, and multiple limit grooves on multiple limit rods are evenly distributed along the bolt head toward the secondary nut, and an annular groove and an annular piston are coaxially provided on the end surface of the bolt close to the secondary nut, and the annular piston is located in the annular groove and is slidably connected with the inner side wall of the annular groove, and a mounting hole is provided on the side of the bolt close to the secondary nut, and the mounting hole passes through the bolt, and the axis of the mounting hole coincides with and is perpendicular to the axis of the bolt. A pressure spring and two sliding rods are provided in the mounting hole, and the pressure spring is provided between the two sliding rods, and both ends are fixedly connected to the two sliding rods respectively, and the two sliding rods are provided with a No. 1 inclined surface on the side away from the pressure spring, and the No. 1 inclined surface faces the direction of the main nut, and a hydraulic hole is provided in the secondary screw, and a pressure relief knob is provided at the rear end of the hydraulic hole, and the pressure relief knob is threadedly connected to the hydraulic hole.

[0011] Through the arrangement of the annular groove and the annular piston, when the secondary nut is screwed into the secondary screw, the secondary nut gradually squeezes the annular piston, and under the action of the hydraulic pressure, the slide rod slides outward and is inserted into the limit groove. If the pressure is insufficient, the pressure relief knob is adjusted to allow the slide rod to be inserted into the limit groove, thereby avoiding the limit rod from sliding and causing the bolt to loosen; further, by arranging a No. 1 inclined plane on the slide rod, when the limit rod slides to the rear end, since the direction of the No. 1 inclined plane is opposite to the direction of the limit rod sliding to the rear end, the limit rod is subjected to the reverse force of the No. 1 inclined plane to avoid the slide rod from sliding to the rear end, thereby ensuring that the bolt will not loosen.

[0012] Preferably, the two sliding rods are provided with a No. 2 inclined surface on the side away from the pressure spring, and the direction of the No. 2 inclined surface is opposite to the loosening direction of the rotation of the secondary nut. A rubber ring is provided in the limiting hole, and the outer wall of the rubber ring is fixedly connected to the inner wall of the limiting hole, and the inner wall of the rubber ring is slidably connected to the limiting rod.

[0013] When the main nut rotates loose due to vibration, the No. 1 washer rotates under the reaction force of the No. 2 washer, and drives the limit rod to rotate. Therefore, the No. 2 inclined surface is set on the slide rod, and the direction of the No. 2 inclined surface is opposite to the rotation direction of the limit rod, thereby avoiding the rotation of the limit rod and ensuring that the bolt will not loosen; further, when the No. 1 serration and the No. 2 serration cannot engage, the slide rod cannot be inserted into the limit groove. By setting a rubber ring in the limit hole, the limit rod squeezes the rubber ring, and then the limit groove is aligned with the slide rod, which ensures that the slide rod is inserted into the limit groove, avoiding the rotation of the limit rod and ensuring that the bolt will not loosen.

[0014] Preferably, a piston rod and a pressure relief spring are provided in the hydraulic hole, the pressure relief spring is located between the piston rod and the pressure relief knob, and both ends of the pressure relief spring are fixedly connected to the piston rod and the pressure relief knob respectively.

[0015] Through the arrangement of the piston rod and the pressure relief spring, when the secondary nut is screwed in, in order to reach the front end of the secondary screw every time, the piston rod is subjected to the hydraulic action and pushes the hydraulic spring to compress, thereby ensuring that the secondary nut reaches the front end of the secondary screw, avoiding the loosening of the bolt caused by the inability of the sliding rod to be inserted into the limit groove, thereby ensuring that the sliding rod can be inserted into the limit groove, so that the limit rod cannot rotate, and further ensuring that the bolt will not loosen.

[0016] Preferably, a locking surface is provided on the outer side wall of the auxiliary bolt, a locking hole is provided in the auxiliary nut, a No. 1 cotter pin is provided in the locking hole, and the No. 1 cotter pin is inserted into the locking hole and abuts against the locking surface.

[0017] A locking surface is provided at the outer end of the secondary bolt and a locking hole is provided in the secondary nut. When the secondary nut is loosened due to vibration, the cotter pin is inserted from the locking hole and abuts against the locking surface. When the secondary nut rotates, the cotter pin and the locking surface are subjected to a reaction force, which prevents the secondary nut from rotating and causing the main nut to rotate, thereby ensuring that the bolt will not loosen.

[0018] Preferably, the diameter of the bolt is D1, the diameter of the sliding rod is D2, 1 / 4*D1≤D2≤1 / 3*D1, the surface of the sliding rod is provided with a nitriding layer, the thickness of the nitriding layer is 0.1mm-0.3mm, and the hardness of the nitriding layer is 55HRC-58HRC.

[0019] By setting the bolt diameter to D1 and the sliding rod diameter to D2, and the 1 / 4*D1≤D2≤1 / 3*D1, the hardness of the sliding rod is guaranteed; further, by providing a nitriding layer on the surface of the sliding rod, the thickness of the nitriding layer is 0.1mm-0.3mm, and the hardness of the nitriding layer is 55HRC-58HRC, the problem of loosening of the bolt due to damage to the sliding rod is avoided, thereby ensuring the hardness of the sliding rod and thus ensuring that the bolt will not loosen.

[0020] Preferably, chamfers are provided at the connections between the plurality of limit rods and the No. 1 washers, and the chamfers are provided on the two side walls corresponding to the forward and reverse rotations of the limit rods and the secondary nut.

[0021] Since the two limit rods and the No. 1 washer rotate in opposite directions to the main nut, the stress will be concentrated at the connection between the limit rods and the No. 1 washer. Therefore, chamfers are set at the connection between the two limit rods and the No. 1 washer to avoid damage to the connection due to stress concentration or excessive torque, which may cause the bolt to loosen. The fatigue strength of the connection between the two limit rods and the No. 1 washer is ensured, thereby ensuring that the bolt will not loosen.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1. The present invention provides a secondary screw and a secondary nut. Since the main nut and the secondary nut rotate in opposite directions, the secondary nut drives the No. 1 washer to rotate in the same direction. Therefore, opposite friction forces are generated between the main nut and the No. 1 washer, thereby avoiding the problem of loosening of the main nut. Furthermore, a tension spring is provided at the rear end of the secondary nut. When the secondary nut rotates toward the rear end due to vibration, the tension spring applies a pressure toward the front end to the secondary nut, making it impossible for the secondary nut to rotate toward the rear end, thereby avoiding loosening of the secondary nut, thereby ensuring that the main nut will not loosen, and further ensuring that the bolt will not loosen.

[0024] 2. The present invention provides an annular groove and an annular piston. When the secondary nut is screwed into the secondary screw, the slide rod slides outward under the action of hydraulic pressure and is inserted into the limit groove. If the pressure is insufficient, the pressure relief knob is adjusted to allow the slide rod to be inserted into the limit groove, thereby avoiding the problem of the limit rod sliding and causing the bolt to loosen. By providing a No. 1 inclined plane on the slide rod, when the limit rod slides toward the rear end, since the direction of the No. 1 inclined plane is opposite to the direction in which the limit rod slides toward the rear end, the limit rod is subjected to the reverse force of the No. 1 inclined plane, thereby avoiding the slide rod sliding toward the rear end, thereby ensuring that the bolt will not loosen.

[0025] 3. The present invention provides a locking surface on the outer end of the secondary bolt and a locking hole in the secondary nut. When the secondary nut becomes loose due to vibration, the cotter pin is inserted from the locking hole and abuts against the locking surface. When the secondary nut rotates, the cotter pin and the locking surface are subjected to a reaction force, thereby preventing the secondary nut from rotating and causing the main nut to rotate, thereby ensuring that the bolt will not loosen. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0027] Figure 2 This is a schematic diagram of the main nut structure of the present invention;

[0028] Figure 3 is a cross-sectional view of the secondary nut of the present invention;

[0029] Figure 4 A top view of the present invention;

[0030] Figure 5 for Figure 4 Cross-sectional view at AA in the middle;

[0031] Figure 6 for Figure 5 A partial enlarged view of middle B;

[0032] In the figure: 1. Bolt; 101. Annular groove; 102. Mounting hole; 2. Auxiliary screw; 201. Hydraulic hole; 202. Locking surface; 3. Main nut; 301. Washer No. 2; 302. Serration No. 2; 4. Auxiliary nut; 401. Locking hole; 402. Limiting hole; 5. Limiting rod; 501. Limiting groove; 6. Washer No. 1; 601. Serration No. 1; 7. Annular piston; 8. Tension spring; 9. Pressure spring; 10. Sliding rod; 1001. Inclined surface No. 1; 1002. Inclined surface No. 2; 11. Pressure relief knob; 12. Rubber ring; 13. Piston rod; 14. Pressure relief spring; 15. Cotter pin No. 1; 16. Fixing nut; 17. Cotter pin No. 2; 18. Washer No. 3; 19. Chamfer. DETAILED DESCRIPTION

[0033] See also Figures 1 to 6 The present invention provides a self-locking double-thread anti-loosening bolt, and the technical solution is as follows:

[0034] See also Figures 1 to 5A self-locking double-threaded anti-loosening bolt comprises a bolt 1 and a main nut 3, the main nut 3 is coaxially threadedly connected to the bolt 1, and is characterized in that a secondary screw rod 2 is coaxially arranged on the end face of the bolt 1 away from the head of the bolt 1, the diameter of the secondary screw rod 2 is smaller than the diameter of the bolt 1, and the thread direction is opposite to that of the bolt 1, and a secondary nut 4 is coaxially threadedly connected to the secondary screw 2, and a plurality of limiting holes 402 are provided on the outer end face of the secondary nut 4, the axis lines of the plurality of limiting holes 402 are parallel to the axis line of the bolt 1, and are evenly distributed along the circumference of the axis of the secondary nut 4, and the plurality of limiting holes 402 are slidably connected to the limiting rods 5, and a number 1 washer 6 is fixedly installed on one end of the plurality of limiting rods 5 close to the main nut 3, and the number 1 washer 6 is fixed on the other end away from the limiting rod 5 The main nut 3 is connected, and a plurality of limit rods 5 are coaxially provided with a tension spring 8, a No. 3 washer 18 and a fixing nut 16 on one end away from the main nut 3. The fixing nut 16 is threadedly connected to the limit rod 5. The two ends of the tension spring 8 are respectively fixedly connected to the secondary nut 4 and the No. 3 washer 18. The two ends of the No. 3 washer 18 are respectively fixedly connected to the tension spring 8 and the fixing nut 16. Fixing holes are provided on the side walls of the fixing nut 16 and the limit rod 5, and a No. 2 cotter pin 17 is coaxially inserted in the fixing hole; a No. 2 washer 301 is provided between the No. 1 washer 6 and the main nut 3, and the end of the No. 2 washer 301 away from the secondary nut 4 is connected to the main nut 3, and the end of the No. 1 washer 6 away from the secondary nut 4 is provided with multiple No. 1 serrations 601, multiple No. 1 serrations 601 is arranged along the circumference of the axis of the No. 1 washer 6, and the direction of the No. 1 serration 601 is opposite to the direction in which the secondary nut 4 is screwed in. The end of the No. 2 washer 301 away from the head of the bolt 1 is provided with multiple No. 2 serrations 302, and multiple No. 2 serrations 302 are arranged along the circumference of the axis of the No. 2 washer 301, and the direction of the No. 2 serrations 302 is the same as the direction in which the secondary nut 4 is screwed in. The No. 1 serration 601 and the No. 2 serration 302 are engaged with each other; multiple limiting grooves 501 are provided on the inner side walls of the multiple limiting rods 5, and the multiple limiting grooves 501 on the multiple limiting rods 5 are evenly distributed along the head of the bolt 1 toward the secondary nut 4. An annular groove 101 and an annular piston 7 are coaxially provided on the end face of the bolt 1 close to the secondary nut 4. The annular piston 7 is located in the annular groove 101 and is slidably connected to the inner wall of the annular groove 101. A mounting hole 102 is provided on the side of the bolt 1 close to the secondary nut 4. The mounting hole 102 passes through the bolt 1. The axis of the mounting hole 102 coincides with and is perpendicular to the axis of the bolt 1. A pressure spring 9 and two slide rods 10 are provided in the mounting hole 102. The pressure spring 9 is arranged between the two slide rods 10, and the two ends are fixedly connected to the two slide rods 10 respectively. The two slide rods 10 are provided with a No. 1 inclined surface 1001 on the side away from the pressure spring 9, and the No. 1 inclined surface 1001 is facing the direction of the main nut 3. A hydraulic hole 201 is provided in the secondary screw 2, and a pressure relief knob 11 is provided at the rear end of the hydraulic hole 201. The pressure relief knob 11 is threadedly connected to the hydraulic hole 201.

[0035] See also Figures 1 to 6, the two slide rods 10 are provided with a second inclined surface 1002 on the side away from the pressure spring 9, and the direction of the second inclined surface 1002 is opposite to the loosening direction of the rotation of the secondary nut 4. A rubber ring 12 is provided in the limiting hole 402, and the outer wall of the rubber ring 12 is fixedly connected to the inner wall of the limiting hole 402, and the inner wall of the rubber ring 12 is slidably connected to the limiting rod 5; a piston rod 13 and a pressure relief spring 14 are provided in the hydraulic hole 201, and the pressure relief spring 14 is located between the piston rod 13 and the pressure relief knob 11, and the two ends of the pressure relief spring 14 are fixedly connected to the piston rod 13 and the pressure relief knob 11 respectively; the secondary bolt 1 A locking surface 202 is provided on the outer wall, a locking hole 401 is provided in the secondary nut 4, a No. 1 cotter pin 15 is provided in the locking hole 401, the No. 1 cotter pin 15 is inserted into the locking hole 401, and abuts against the locking surface 202; the diameter of the bolt 1 is 20 mm, the diameter of the sliding rod 10 is 5 mm, and the surface of the sliding rod 10 is provided with a nitriding layer, the thickness of the nitriding layer is 0.3 mm, and the hardness of the nitriding layer is 58 HRC; a chamfer 19 is provided at the connection between the multiple limit rods 5 and the No. 1 washer 6, and the chamfer 19 is provided on the two side walls corresponding to the forward and reverse rotation of the limit rod 5 and the secondary nut 4.

[0036] See also Figures 1 to 6When the main nut 3 is loosened, the secondary nut 4 is tightened and the secondary nut 4 is locked. To prevent loosening, the front end of the tension spring 8 applies pressure to the secondary nut 4 to prevent it from rotating in the loosening direction, thereby achieving the anti-loosening effect of the secondary nut 4; when the secondary nut 4 is screwed into the front end of the secondary screw 2, the annular piston 7 is pushed, and the two slide rods 10 are pushed out from the mounting hole 102 by the hydraulic force and inserted into the limiting groove 501 on the limiting rod 5. The excess pressure pushes the piston rod 13 to squeeze the pressure relief spring 14, so that the secondary nut 4 can be screwed into the front end of the secondary screw 2, and the slide rod 10 The No. 1 bevel 1001 on it prevents the limit rod 5 from sliding toward the secondary screw 2, and the No. 2 bevel 1002 prevents the limit rod 5 from rotating; when disassembling, turn the pressure relief knob 11 to make the pressure spring 9 pull the slide rod 10 back into the mounting hole 102, pull out the No. 1 cotter pin 15 and the No. 2 cotter pin 17, twist out the fixing nut 16, take out the tension spring 8, pull the limit rod 5 to make the No. 1 serration 601 and the No. 2 serration 302 engage and separate, then unscrew the secondary nut 4, and finally unscrew the main nut 3.

[0037] A specific embodiment of the present invention has been described in detail above with reference to the accompanying drawings, but the present invention is not limited to the embodiment described above. For those skilled in the art, various changes, modifications, substitutions, and variations to these embodiments without departing from the principles and ideas of the present invention should still fall within the scope of protection of the present invention.

Claims

1. A self-locking double-threaded anti-loosening bolt, comprising a bolt (1) and a main nut (3), wherein the main nut (3) is coaxially threadedly connected to the bolt (1), characterized in that: A secondary screw rod (2) is coaxially arranged on the end face of the bolt (1) away from the head of the bolt (1). The diameter of the secondary screw rod (2) is smaller than the diameter of the bolt (1) and the thread direction is opposite to that of the bolt (1). A secondary nut (4) is coaxially threadedly connected to the secondary screw rod (2). A plurality of limiting holes (402) are opened on the outer end face of the secondary nut (4). The axis lines of the plurality of limiting holes (402) are parallel to the axis line of the bolt (1) and are evenly distributed along the circumference of the axis of the secondary nut (4). A limiting rod (5) is slidably connected in the plurality of limiting holes (402). A number 1 washer (6) is fixedly installed on one end of the plurality of limiting rods (5) close to the main nut (3). The end of the No. 1 washer (6) away from the limiting rod (5) is connected to the main nut (3), and a tension spring (8), a No. 3 washer (18) and a fixing nut (16) are coaxially arranged on the end of the plurality of limiting rods (5) away from the main nut (3). The fixing nut (16) is threadedly connected to the limiting rod (5). The two ends of the tension spring (8) are respectively fixedly connected to the auxiliary nut (4) and the No. 3 washer (18). The two ends of the No. 3 washer (18) are respectively fixedly connected to the tension spring (8) and the fixing nut (16). The side walls of the fixing nut (16) and the limiting rod (5) are both provided with fixing holes, and a No. 2 cotter pin (17) is coaxially inserted into the fixing hole.

2. A self-locking double-thread anti-loosening bolt according to claim 1, characterized in that: A No. 2 washer (301) is provided between the No. 1 washer (6) and the main nut (3), and the end of the No. 2 washer (301) away from the secondary nut (4) is connected to the main nut (3). The end of the No. 1 washer (6) away from the secondary nut (4) is provided with a plurality of No. 1 serrations (601), the plurality of No. 1 serrations (601) are arranged along the circumference of the axis of the No. 1 washer (6), and the direction of the No. 1 serrations (601) is opposite to the direction in which the secondary nut (4) is screwed in. The end of the No. 2 washer (301) away from the head of the bolt (1) is provided with a plurality of No. 2 serrations (302), the plurality of No. 2 serrations (302) are arranged along the circumference of the axis of the No. 2 washer (301), and the direction of the No. 2 serrations (302) is the same as the direction in which the secondary nut (4) is screwed in. The No. 1 serrations (601) and the No. 2 serrations (302) are meshed with each other.

3. A self-locking double-thread anti-loosening bolt according to claim 1, characterized in that: A plurality of limiting grooves (501) are provided on the inner side walls of the plurality of limiting rods (5), and the plurality of limiting grooves (501) on the plurality of limiting rods (5) are evenly distributed along the head of the bolt (1) toward the auxiliary nut (4). An annular groove (101) and an annular piston (7) are coaxially provided on the end face of the bolt (1) close to the auxiliary nut (4). The annular piston (7) is located in the annular groove (101) and is slidably connected to the inner side wall of the annular groove (101). A mounting hole (102) is provided on the side of the bolt (1) close to the auxiliary nut (4). The mounting hole (102) passes through the bolt (1), and the axis of the mounting hole (102) is The center line coincides with and is perpendicular to the axis line of the bolt (1); a pressure spring (9) and two slide bars (10) are provided in the mounting hole (102); the pressure spring (9) is provided between the two slide bars (10), and both ends are fixedly connected to the two slide bars (10); a first inclined surface (1001) is provided on the side away from the pressure spring (9) of the two slide bars (10); the first inclined surface (1001) faces the main nut (3); a hydraulic hole (201) is provided in the auxiliary screw (2); a pressure relief knob (11) is provided at the rear end of the hydraulic hole (201); the pressure relief knob (11) is threadedly connected to the hydraulic hole (201).

4. A self-locking double-thread anti-loosening bolt according to claim 3, characterized in that: The two sliding rods (10) are each provided with a second inclined surface (1002) on the side away from the pressure spring (9), and the direction of the second inclined surface (1002) is opposite to the loosening direction of the rotation of the secondary nut (4). A rubber ring (12) is provided in the limiting hole (402), and the outer wall of the rubber ring (12) is fixedly connected to the inner wall of the limiting hole (402), and the inner wall of the rubber ring (12) is slidably connected to the limiting rod (5).

5. A self-locking double-thread anti-loosening bolt according to claim 3, characterized in that: A piston rod (13) and a pressure relief spring (14) are provided in the hydraulic hole (201). The pressure relief spring (14) is located between the piston rod (13) and the pressure relief knob (11). Both ends of the pressure relief spring (14) are fixedly connected to the piston rod (13) and the pressure relief knob (11), respectively.

6. A self-locking double-thread anti-loosening bolt according to claim 3, characterized in that: A locking surface (202) is provided on the outer wall of the auxiliary bolt (1), a locking hole (401) is provided in the auxiliary nut (4), a No. 1 cotter pin (15) is provided in the locking hole (401), and the No. 1 cotter pin (15) is inserted into the locking hole (401) and abuts against the locking surface (202).

7. A self-locking double-thread anti-loosening bolt according to claim 3, characterized in that: The diameter of the bolt (1) is D1, the diameter of the slide rod (10) is D2, 1 / 4*D1≤D2≤1 / 3*D1, the surface of the slide rod (10) is provided with a nitriding layer, the thickness of the nitriding layer is 0.1mm-0.3mm, and the hardness of the nitriding layer is 55HRC-58HRC.

8. The self-locking double-thread anti-loosening bolt according to claim 1, characterized in that: The connection points between the plurality of limiting rods (5) and the No. 1 washer (6) are provided with chamfers (19), and the chamfers (19) are provided on two side walls corresponding to the forward and reverse rotations of the limiting rods (5) and the auxiliary nut (4).

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