A new type of shaft head nut structure with fixed locking torque

Abstract

The invention relates to a novel shaft head nut structure with a fixed locking torque, comprising a wear-resistant gasket, a nut assembly and a limiting component, wherein the nut assembly comprises a nut seat, a gear ring and a butterfly spring, a wear-resistant gasket accommodating cavity is arranged at one end of the nut seat facing the shaft head, a part of the wear-resistant gasket is located in the wear-resistant gasket accommodating cavity and the other part is exposed outside the wear-resistant gasket accommodating cavity and is used to contact with the bearing, which can reduce the direct wear between the nut seat and the bearing, and ensure that the bearing is in the best assembly state for a long time; a gear ring accommodating groove and a spring clamping groove are arranged on the outer peripheral surface of the nut seat, the gear ring is sleeved in the gear ring accommodating groove, the gear ring is meshed with the nut seat and the two can only mesh and rotate relative to each other in one direction; the outer side of the butterfly spring is against the gear ring so that the gear ring and the nut seat remain meshed, thereby ensuring the best locking torque, achieving the best performance and service life of the wheel hub system, and completely avoiding the problem of early failure of the bearing caused by excessive or insufficient locking torque.

Description

Technical Field

[0001] The invention relates to the technical field of vehicle engineering technology, in particular to a novel shaft head nut structure for fixing locking torque. Background Art

[0002] The existing automobile axle hub, especially the heavy-duty automobile axle hub, generally adopts a pair of tapered roller bearings installed back to back to bear the load-bearing and rotation functions of the axle. The installation accuracy and preload force of the bearing play a vital role in the performance and life of the bearing. According to different axle loads, bearing sizes and hub sizes, the round shaft roller bearings installed in pairs have the best locking torque to achieve the best performance and life. The mainstream host manufacturers in the industry generally use servo wrenches or manual torque wrenches for locking, while the maintenance outlets in the after-sales market usually use simple wrenches for locking, which can easily cause the bearing locking torque to be too large or too small, resulting in the bearing failing to reach its service life, and even causing early failures leading to serious safety accidents. In addition, because the bearing will wear the locking parts under long-term working conditions, the bearing installation accuracy will be gradually lost in later use, reducing the service life of the bearing. Summary of the invention

[0003] In order to solve the above problems, the present invention provides a novel shaft head nut structure with a fixed locking torque, which is used to lock and compress the bearing, ensure the installation accuracy of the bearing, and prevent the locking torque from being too large or too small, causing the bearing to fail prematurely.

[0004] To achieve the above purpose, the present invention provides the following technical solutions:

[0005] A novel shaft head nut structure for fixing locking torque, comprising a wear-resistant gasket 2, a nut assembly 3 and a limiting component 4 for limiting the nut assembly 3 which are sequentially sleeved on the shaft head 1, the nut assembly 3 comprising a nut seat 31 sleeved on the shaft head 1 and a gear ring 32 and a butterfly spring 33 sleeved on the nut seat 31, the nut seat 31 is provided with a wear-resistant gasket accommodating cavity 310 at one end facing the shaft head 1, the other end of the nut seat 31 is formed with a spring slot 312 by bending, a part of the wear-resistant gasket 2 is located in the wear-resistant gasket accommodating cavity 310 and contacts with the wear-resistant gasket accommodating cavity 310, and the other part of the wear-resistant gasket 2 is exposed outside the wear-resistant gasket accommodating cavity 310 and is used to contact with the bearing 5; the nut A gear ring accommodating groove 311 is provided on the outer peripheral surface of the seat 31, and the gear ring 32 is inserted into the gear ring accommodating groove 311. A plurality of first teeth 313 are distributed in an annular array on the groove wall of the gear ring accommodating groove 311, and a first tooth groove 314 is formed between adjacent first teeth 313. The gear ring 32 is provided with second teeth 321 meshing with the first teeth 313, and a second tooth groove 322 is formed between adjacent second teeth 321. The gear ring 32 and the nut seat 31 can only mesh and rotate relative to each other in one direction; the butterfly spring 33 is in the shape of an annular sheet, and the inner side of the butterfly spring 33 is inserted into the spring clamping groove 312, and the outer side of the butterfly spring 33 presses against the gear ring 32 so that the gear ring 32 and the nut seat 31 remain meshed.

[0006] As a preferred embodiment, it is further defined as: the limit assembly 4 includes a spring retaining ring 41 and a latch 42, the middle part of the nut seat 31 has a first axial hole 315 for the shaft head 1 to pass through, the wear-resistant gasket accommodating chamber 310 is located on one side of the first axial hole 315 and communicates with it, the inner wall of the other side of the first axial hole 315 is provided with a plurality of internal teeth 316 distributed in a circular array, the outer peripheral surface of the shaft head 1 is provided with a limit groove 10 extending along its axial direction and communicating with the first axial hole 315, the latch 42 is inserted between the limit groove 10 and the first axial hole 315, and the latch 42 is provided with external teeth 421 meshing with the internal teeth 316; the spring retaining ring 41 is sleeved on the shaft head 1 and fixedly connected with the latch 42.

[0007] As a preferred embodiment, it is further defined as: a through hole 420 is provided at the side end of the latch 42 , the spring collar 41 is annular, and the upper end of the spring collar 41 is bent downward and passes through the through hole 420 .

[0008] As a preferred embodiment, it is further defined as: the number of teeth of the inner teeth 316 is 50 to 100; the tooth shape of the inner teeth 316 is consistent with that of the outer teeth 421 .

[0009] As a preferred embodiment, it is further defined as: a second axial hole 20 for the shaft head 1 to pass through is provided in the middle of the wear-resistant gasket 2, and the wear-resistant gasket 2 is provided with a protrusion 21 extending into the second axial hole 20, and after assembly, the protrusion 21 is located in the limiting groove 10.

[0010] As a preferred embodiment, it is further defined as: the end of the nut seat 31 facing the shaft head 1 is provided with a flange portion 317 which is flanged outward from the top end of the wear-resistant gasket accommodating cavity 310 .

[0011] As a preferred embodiment, it is further defined as: the meshing angle between the first tooth 313 and the second tooth 321 is 33±5°.

[0012] As a preferred implementation, it is further defined as: the number of teeth of the first teeth 313 is 10-15 teeth.

[0013] As a preferred embodiment, it is further defined as: the cross-section of the first tooth 313 is a right-angled trapezoid, wherein the first vertex angle and the first bottom angle of one waist are both right angles, and the angle of the second bottom angle of the other waist is 33±5°; the second tooth 321 is a right-angled trapezoid, wherein the second vertex angle and the third bottom angle of one waist are both right angles, and the angle of the fourth bottom angle of the other waist is 33±5°.

[0014] As a preferred embodiment, it is further defined as: the first top angle and the second top angle are both provided with chamfers, a chamfer is provided between the first bottom angle and the first tooth groove 314, and a chamfer is provided between the first bottom angle and the second tooth groove 322; the outer peripheral surface of the gear ring 32 is hexagonal.

[0015] The beneficial effects of the present invention are:

[0016] 1. The invention includes a wear-resistant gasket, a nut assembly and a limit assembly. The nut assembly includes a nut seat, a gear ring and a butterfly spring. The nut seat is provided with a wear-resistant gasket accommodating cavity at one end facing the shaft head. A part of the wear-resistant gasket is located in the wear-resistant gasket accommodating cavity and the other part is exposed outside the wear-resistant gasket accommodating cavity and is used to contact the bearing, which can reduce the direct wear between the nut seat and the bearing and ensure that the bearing is in the best assembly state for a long time.

[0017] 2. A gear ring accommodating groove and a spring retaining groove are provided on the outer circumferential surface of the nut seat. The gear ring is inserted into the gear ring accommodating groove. The gear ring is meshed with the nut seat and the two can only rotate relative to each other in one direction. The outer side of the butterfly spring is pressed against the gear ring to keep the gear ring and the nut seat meshed, ensuring the best locking torque, achieving the best performance and service life of the wheel hub system, and completely avoiding the problem of early failure of the bearing due to excessive or insufficient locking torque. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of the invention;

[0019] Figure 2 It is a schematic diagram of the structural decomposition of the present invention;

[0020] Figure 3 It is a schematic diagram of the structure cutaway of the present invention;

[0021] Figure 4 is a structural schematic diagram of a nut assembly;

[0022] Figure 5 It is a schematic diagram of the structural breakdown of the nut assembly;

[0023] Figure 6 It is a structural schematic diagram of the nut seat;

[0024] Figure 7 It is a schematic diagram of the structure of the ring gear;

[0025] Figure 8 It is a structural schematic diagram of the limit assembly;

[0026] Fig. 9 It is a schematic diagram of the structure of the wear-resistant gasket. DETAILED DESCRIPTION

[0027] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments:

[0028] As attached Figure 1 To Attachment Fig. 9As shown, a new type of shaft head nut structure with fixed locking torque includes a wear-resistant gasket 2, a nut assembly 3 and a limiting component 4 for limiting the nut assembly 3, which are sequentially mounted on the shaft head 1. The nut assembly 3 includes a nut seat 31 mounted on the shaft head 1, a gear ring 32 and a butterfly spring 33 mounted on the nut seat 31. The end of the shaft head 1 adopts a threaded design, and the nut seat 31 is provided with a thread that is threadedly connected to the shaft head 1. The two are assembled by threaded tightening. The nut seat 31 is provided with a wear-resistant gasket accommodating cavity 310 at one end facing the shaft head 1, and the other end of the nut seat 31 is bent by a "spinning" process to form a spring groove 312, a part of the wear-resistant gasket 2 is located in the wear-resistant gasket accommodating cavity 310 and contacts with the wear-resistant gasket accommodating cavity 310, and the other part of the wear-resistant gasket 2 is exposed outside the wear-resistant gasket accommodating cavity 310 and is used to contact with the bearing 5; that is, the depth of the wear-resistant gasket accommodating cavity 310 is less than the thickness of the wear-resistant gasket 2, so that the wear-resistant gasket 2 can be tightly attached to the nut seat 31 and the bearing 5, so that the wear-resistant gasket 2 can separate the nut seat 31 and the bearing 5 to avoid direct friction between the two. Since the wear-resistant gasket adopts a strengthening or surface strengthening process, it provides wear-resistant performance and can ensure that the bearing maintains a good installation accuracy for a long time. A gear ring accommodating groove 311 is provided on the outer circumferential surface of the nut seat 31, and the gear ring accommodating groove 311 is connected with the spring retaining groove 312, and the gear ring 32 is sleeved in the gear ring accommodating groove 311, and a plurality of first teeth 313 are distributed in an annular array on the groove wall of the gear ring accommodating groove 311, and a first tooth groove 314 is formed between adjacent first teeth 313, and the gear ring 32 is provided with second teeth 321 meshing with the first teeth 313, and a second tooth groove 322 is formed between adjacent second teeth 321, and the gear ring 32 and the nut seat 31 can only rotate in relative meshing in one direction; the butterfly spring 33 is in the shape of an annular sheet, and the inner side of the butterfly spring 33 is inserted into the spring retaining groove 312, and the outer side of the butterfly spring 33 presses against the gear ring 32 so that the gear ring 32 and the nut seat 31 remain meshed. Ensure the best locking torque to achieve the best performance and service life of the hub system, and completely avoid the problem of premature bearing failure caused by excessive or insufficient locking torque.

[0029] In this embodiment, the limiting assembly 4 includes a spring retaining ring 41 and a latch 42, the middle portion of the nut seat 31 has a first axial hole 315 for the shaft head 1 to pass through, the wear-resistant gasket accommodating chamber 310 is located on one side of the first axial hole 315 and communicates with it, the inner wall of the other side of the first axial hole 315 is provided with a plurality of internal teeth 316 distributed in a circular array, the outer peripheral surface of the shaft head 1 is provided with a limiting groove 10 extending along its axial direction and communicating with the first axial hole 315, the latch 42 is inserted between the limiting groove 10 and the first axial hole 315, and the latch 42 is provided with external teeth 421 meshing with the internal teeth 316; the spring retaining ring 41 is sleeved on the shaft head 1 and fixedly connected to the latch 42, and the nut seat 31 is axially fixed by the latch 42. The number of teeth of the inner teeth 316 is 50 to 100, and the optimal design number of teeth is in the range of 50 to 80; the inner teeth 316 and the outer teeth 421 have the same tooth shape and can mesh with each other. The width of the limit groove 10 is slightly wider than the width of the latch 42. The main purpose of this design is to allow the latch 42 to be inserted into the nut seat 31 and mesh with the inner teeth 316 regardless of the locking rotation angle of the nut assembly 3. A through hole 420 is provided at the side end of the latch 42. The spring retaining ring 41 is annular, and the upper end of the spring retaining ring 41 is bent downward (recessed design) and then passes through the through hole 420. The lower end of the spring retaining ring 41 can be opened. After the latch 42 is inserted into the limit groove 10 to fix the nut assembly 3, the spring retaining ring 41 can be opened so that the spring retaining ring 41 is stuck into the end of the nut assembly 3 to prevent the spring retaining ring 41 and the latch 42 from falling off.

[0030] In this embodiment, the middle of the wear-resistant gasket 2 is provided with a second shaft hole 20 for the shaft head 1 to pass through, and the wear-resistant gasket 2 is provided with a protrusion 21 extending into the second shaft hole 20. After assembly, the protrusion 21 is located in the limiting groove 10, and the protrusion 21 has a limiting effect on the wear-resistant gasket 2. The wear-resistant gasket 2 adopts a thin ring structure, and is strengthened by overall quenching, induction quenching, carburizing and other strengthening processes to improve the wear resistance of the wear-resistant gasket.

[0031] In this embodiment, the nut seat 31 is formed by metal forging and machined according to the design. It can be seen that the nut seat 31 is flange-shaped as a whole, and the first shaft hole 315 is threaded and connected with the thread of the end of the axle head 1; the end with a larger diameter is designed with an annular countersunk hole to form the wear-resistant gasket accommodating cavity 310. The end of the nut seat 31 facing the shaft head 1 is provided with a flange portion 317 that is flanged from the top of the wear-resistant gasket accommodating cavity 310 to the outside.

[0032] In this embodiment, the meshing angle between the first teeth 313 and the second teeth 321 is 33±5°, and the optimal angle is 33°. The number of teeth of the first teeth 313 is 10-15 teeth, and the optimal number of teeth is 12 teeth. Furthermore, the cross section of the first teeth 313 is a right-angled trapezoid, wherein the first vertex angle and the first bottom angle of one waist are both right angles, and the angle of the second bottom angle of the other waist is 33±5°, and the optimal angle is 33°; the second teeth 321 are a right-angled trapezoid, wherein the second vertex angle and the third bottom angle of one waist are both right angles, and the angle of the fourth bottom angle of the other waist is 33±5°, and the optimal angle is 33°. The small head end of the nut seat 31 is machined into a thin ring shape, which can be inserted to accommodate the butterfly spring 33. The thin ring design can be used to use the "spinning" process to turn the lip of the nut seat 31 to press the butterfly spring 33 after the butterfly spring 33 is inserted. The first top angle and the second top angle are both provided with chamfers, the first bottom angle and the first tooth groove 314 are provided with a chamfer, and the first bottom angle and the second tooth groove 322 are provided with a chamfer. In this embodiment, during the clockwise locking process, the angle can be climbed, and during the counterclockwise reversal process, the first tooth 313 and the second tooth 321 are in positive right-angle contact, which can prevent reverse installation.

[0033] In this embodiment, the outer peripheral surface of the gear ring 32 is hexagonal. The gear ring 32 can be formed by injection molding of engineering plastics, or by pressing and sintering of powder metallurgy. The number of teeth of the second teeth 321 corresponds to the number of teeth of the first teeth 313. There are no special requirements for the end face of the gear ring 32 away from the second teeth 321, as long as it has a flat and positionable surface. The gear ring formed by injection molding can adopt a "honeycomb" design to save materials, but the end face should be basically flat so that the butterfly spring 33 can be positioned and pressed.

[0034] In this embodiment, the butterfly spring 33 is made of a thin sheet spring steel material, which is generally annular and formed into a cone through a press forming process. The hardness of the material is then strengthened to a hardness of HRC45 to 55 through a heat treatment process, and has good elasticity. At this time, when axial pressure is applied to the butterfly spring 33, the butterfly spring 33 will generate a reverse elastic force.

[0035] The installation process of the nut assembly 3 is as follows: the gear ring 32 is inserted into the nut seat 31, so that the tooth surfaces of the two are interlocked, and the small-angle cone surfaces are in contact with each other. The butterfly spring 33 is inserted into the nut seat 31 in sequence, with the larger annular side close to the non-toothed end surface of the gear ring 32, and the smaller annular side close to the lip of the nut seat 31. At this time, the lip is slightly higher than the butterfly spring 33. The lip is flanged by the "spinning" process, and the butterfly spring 33 is pressed. After the lip is flanged, the spring slot 312 is formed, and the assembly of the nut assembly 3 is completed.

[0036] During the assembly process, the hexagonal sleeve is used to rotate the nut assembly 3 clockwise, and the nut assembly 3 drives the wear-resistant gasket 2 until it is close to the end face of the bearing 5. Due to the continuous thread damping, the relative positions of the ring gear 32 and the nut seat 31 will not change. When the wear-resistant gasket 2 is close to the end face of the bearing 5, the nut seat 31 can no longer rotate. At this time, the sleeve continues to twist the ring gear 32 clockwise, and the small-angle tooth surface of the ring gear 32 will slide and climb along the small-angle tooth surface of the nut seat 31, forcing the ring gear 32 to move backward, and the back side of the ring gear 32 will compress the butterfly spring 33. The butterfly spring 33 generates a reaction force on the ring gear 32 due to the compression, thereby generating a certain locking torque. As the small-angle tooth surface of the gear ring 32 continues to slide and climb along the small-angle tooth surface of the nut seat 31, the reaction force generated by the butterfly spring 33 continues to increase until the small-angle tooth surface climbs to the apex of the tooth shape, and the teeth of the gear ring 32 and the nut seat 31 slide on the top end surface. At this time, the displacement of the gear ring 32 relative to the nut seat 31 reaches a maximum value, and the compression of the butterfly spring 33 also reaches a maximum value, and the maximum reaction force is generated on the gear ring 32. At this time, the torque of the socket wrench rotating the gear ring 32 is the preset locking torque, and the pressure applied to the bearing 5 by the nut seat 31 through the wear-resistant gasket 2 no longer increases, thereby generating a preset preload force on the bearing 5. At this time, the toothed ring 32 is continuously rotated by the socket wrench, and the tooth top of the toothed ring 32 will fall into the tooth bottom of the tooth shape of the nut seat 31 (in the first tooth groove 314), and the butterfly spring 33 will press the toothed ring 32 back to the original axial position, thereby continuously rotating the toothed ring 32 clockwise, and the toothed ring will repeat the above action. The locking torque can only reach the torque generated when the tooth tops of the toothed ring 32 and the nut seat 31 contact, realizing the function of fixing the locking torque, and the pressure applied to the bearing 5 by the nut seat 31 through the wear-resistant gasket 2 will also remain constant. After locking the nut assembly 3, insert the pin 42 into the limit groove 10 according to the above introduction, fix the nut assembly 3, and clamp the spring retaining ring 41 into the end flange position of the nut assembly 3 (in the spring retaining groove 312) to complete the entire assembly process.

[0037] The preset locking torque is determined by the design of the tooth profiles (the first teeth 313 and the second teeth 321) of the ring gear 32 and the nut seat 31, the elastic properties of the butterfly spring 33 and the height of the lip flange of the nut seat 31, and can be achieved by adjusting the above-mentioned determining factors according to the optimal preload force of different wheel hub bearings.

[0038] When the nut assembly 3 needs to be disassembled, it is only necessary to unplug the spring retaining ring 41, pull out the pin 42, and use the sleeve to rotate the nut assembly 3 counterclockwise. Since the tooth profiles of the ring gear 32 and the nut seat 31 are in contact at a 90° right angle when they rotate counterclockwise, the ring gear 32 will directly lead the nut assembly 3 to rotate as the sleeve rotates counterclockwise until the nut assembly 3 is completely unscrewed, completing the disassembly process.

[0039] From the above functional introduction, it can be seen that only a simple sleeve nut is used to ensure the consistency of the locking torque, and the installation process is simple and easy without the need for a professional torque wrench. In addition, the tooth top of the gear ring 32 will instantly fall into the first tooth groove 314 of the nut seat 31. Since the parts will make a "click" sound due to collision, there is obvious locking feedback during the locking process, which can clearly remind the operator that the locking process has been completed, and completely solve the problem of bearing failure due to excessive or insufficient locking torque.

Claims

1. A novel shaft head nut structure for fixing the locking torque, comprising a wear-resistant gasket (2) sequentially mounted on a shaft head (1), a nut assembly (3), and a limiting component (4) for limiting the position of the nut assembly (3), The nut assembly (3) comprises a nut seat (31) sleeved on the shaft head (1), and a gear ring (32) and a butterfly spring (33) sleeved on the nut seat (31); the butterfly spring (33) is in the shape of an annular sheet; A gear ring accommodating groove (311) is provided on the outer peripheral surface of the nut seat (31), the gear ring (32) is sleeved in the gear ring accommodating groove (311), a plurality of first teeth (313) are distributed in an annular array on the groove wall of the gear ring accommodating groove (311), a first tooth groove (314) is formed between adjacent first teeth (313), the gear ring (32) is provided with second teeth (321) meshing with the first teeth (313), a second tooth groove (322) is formed between adjacent second teeth (321), and the gear ring (32) and the nut seat (31) can only mesh and rotate relative to each other in one direction; The nut seat (31) has a first axial hole (315) in the middle for the shaft head (1) to pass through, and a wear-resistant gasket accommodating cavity (310) is provided at one end of the nut seat (31) facing the shaft head (1), and the wear-resistant gasket accommodating cavity (310) is located on one side of the first axial hole (315) and communicates with it, a part of the wear-resistant gasket (2) is located in the wear-resistant gasket accommodating cavity (310) and contacts with the wear-resistant gasket accommodating cavity (310), and another part of the wear-resistant gasket (2) is exposed outside the wear-resistant gasket accommodating cavity (310) and is used to contact with the bearing (5), and a second axial hole (20) is provided in the middle of the wear-resistant gasket (2) for the shaft head (1) to pass through, and a plurality of internal teeth (316) distributed in a ring array are provided on the inner wall of the other side of the first axial hole (315) of the nut seat (31); The limit assembly (4) comprises a spring collar (41) and a latch (42), the latch (42) being provided with external teeth (421) meshing with internal teeth (316), the spring collar (41) being sleeved on the shaft head (1) and fixedly connected to the latch (42); It is characterized in that The other end of the nut seat (31) is bent to form a thin ring-shaped flange, and a spring slot (312) is formed next to the flange. The inner side of the butterfly spring (33) is inserted into the spring slot (312), and the outer side of the butterfly spring (33) is pressed against the gear ring (32) so that the gear ring (32) and the nut seat (31) are kept in meshing. The installation process of the nut assembly (3) is as follows: the gear ring (32) is inserted into the nut seat (31) so that the gears of the two are in meshing relationship. The surfaces are interlocked with each other, wherein the small-angle conical surfaces are in contact with each other, and the butterfly spring (33) is inserted into the nut seat (31) in sequence, with the larger annular side close to the non-toothed end surface of the gear ring (32), and the smaller annular side close to the lip of the nut seat (31). At this time, the lip is slightly higher than the butterfly spring (33), and the lip is flanged by a "spinning" process to press the butterfly spring (33). After the lip is flanged, the spring slot (312) is formed, and the assembly of the nut assembly (3) is completed; A limiting groove (10) extending in the axial direction and communicating with the first shaft hole (315) is provided on the outer peripheral surface of the shaft head (1); the wear-resistant gasket (2) is provided with a protrusion (21) extending into the second shaft hole (20); after assembly, the protrusion (21) is located in the limiting groove (10); the latch (42) is inserted between the limiting groove (10) and the first shaft hole (315); the protrusion (21) and the latch (42) are respectively inserted into the two ends of the limiting groove (10).

2. The novel shaft head nut structure with fixed locking torque according to claim 1 is characterized in that: A through hole (420) is provided at the side end of the latch pin (42); the spring retaining ring (41) is annular; the upper end of the spring retaining ring (41) is bent downward and passes through the through hole (420); the butterfly spring (33) is made of a thin sheet of spring steel material and is annular as a whole. It is formed into a cone through a press forming process, and then the hardness of the material is strengthened to a hardness of HRC45 to 55 through a heat treatment process. At this time, when axial pressure is applied to the butterfly spring (33), the butterfly spring (33) will generate a reverse elastic force.

3. The novel shaft head nut structure with fixed locking torque according to claim 2 is characterized in that: The number of teeth of the inner teeth (316) is between 50 and 100; the tooth shape of the inner teeth (316) is consistent with that of the outer teeth (421).

4. The novel shaft head nut structure with fixed locking torque according to claim 2 is characterized in that: One end of the nut seat (31) facing the shaft head (1) is provided with a flange portion (317) flanged outward from the top end of the wear-resistant gasket accommodating cavity (310).

5. The novel shaft head nut structure for fixing the locking torque according to any one of claims 1 to 4, characterized in that: The meshing angle between the first tooth (313) and the second tooth (321) is 33±5°.

6. The novel shaft head nut structure with fixed locking torque according to claim 5 is characterized in that: The number of teeth of the first teeth (313) is 10-15 teeth.

7. The novel shaft head nut structure for fixing the locking torque according to claim 6 is characterized in that: The cross section of the first tooth (313) is a right-angled trapezoid, wherein the first vertex angle and the first bottom angle of one waist are both right angles, and the angle of the second bottom angle of the other waist is 33±5°; the second tooth (321) is a right-angled trapezoid, wherein the second vertex angle and the third bottom angle of one waist are both right angles, and the angle of the fourth bottom angle of the other waist is 33±5°.

8. The novel shaft head nut structure for fixing the locking torque according to claim 7 is characterized in that: The first top angle and the second top angle are both provided with chamfers, a chamfer is provided between the first bottom angle and the first tooth groove (314), and a chamfer is provided between the first bottom angle and the second tooth groove (322); and the outer peripheral surface of the gear ring (32) is hexagonal.

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