CN219605760U - Screw fastening structure - Google Patents

Abstract

The present disclosure provides a screw fastening structure for fastening a pretension member, the screw fastening structure comprising: the screw rod of the bolt penetrates through the pre-tightening piece and partially protrudes out of the pre-tightening piece; the first lock nut for with the screw rod protrusion in the partial threaded connection of pretension piece, it includes: the first part and the second part are coaxially arranged with the bolt, and when the first lock nut is connected with the screw rod, the first part is close to the pre-tightening piece than the second part; the second lock nut is provided with a through hole which extends along the axial direction of the second lock nut and can be penetrated by the screw rod, a threaded part which is used for being in threaded connection with the second part is arranged on the hole wall of the through hole close to the first end, a fastening gasket is arranged in the through hole and between the threaded part and the second end, and when the first lock nut and the second lock nut are locked, the fastening gasket generates plastic deformation and compresses the screw rod so as to limit the relative position of the first lock nut and the screw rod; wherein the first end and the second end are two opposite ends of the second lock nut in the axial direction.

Description

screw fastening structure

technical field

The present disclosure relates to the technical field of thread fastening, in particular to a thread fastening structure.

Background technique

Bolts and nuts are common threaded fasteners, which are usually used together to realize the fastening connection of pretensioned parts through threaded cooperation. When the bolt is connected with the nut, due to mechanical vibration and other reasons, the threaded fastener is very easy to loose after working for a period of time. The greater the vibration of the outside world, the more serious this phenomenon will be, resulting in potential safety hazards. For threaded fastening connections, the most important issue is how to achieve long-term fastening of the pretensioner, that is, to prevent the nut from rotating relative to the bolt to prevent the nut from loosening.

At present, the schemes of nut loosening are mainly divided into two categories: frictional locking and mechanical locking. The two types of nut anti-loosening schemes mainly have the following structural forms: one is the ordinary double-nut structure, that is, two ordinary nuts are fastened on the bolts in sequence to form a series arrangement, and one end of one nut is pressed against the object to be fastened, The other end is pressed by another nut, therefore, both ends of the nut are stressed at the same time, which can delay the loosening time; one is the eccentric double nut structure, the bolts pass through the two nuts at the same time and the two nuts are partially nested before turning At the same time, the through holes of the two nuts are set eccentrically. After the two nuts are rotated relative to each other, the through holes of the two nuts are no longer centered, thereby reducing the diameter of the two nuts and firmly locking the bolts; one is to use a spring washer. Through the threaded fit between the nut and the bolt, the spring washer is located between the pretensioner and the nut and undergoes elastic deformation, increasing the friction between the spring washer and the nut. The greater the thread locking torque, the greater the friction. The anti-loosening of the nut is realized by the friction force generated by the elastic deformation of the spring washer.

Among the above several anti-loosening schemes for nuts, the anti-loosening effect of the ordinary double-nut structure and the anti-loosening scheme using spring washers decreases rapidly with the aggravation of the vibration intensity. In the anti-loosening scheme of the eccentric double-nut structure, the bolt and After the nut thread is locked, it is not easy to disassemble and replace. Therefore, how to propose a more effective nut anti-loosening scheme for the thread locking structure between the bolt and the nut, so that the anti-loosening effect between the bolt and the nut will not be reduced with severe vibration, and it is easy to disassemble after locking And replacing bolts and nuts is an urgent problem to be solved at present.

Utility model content

A technical problem to be solved in the present disclosure is: how to solve the technical problem of preventing loosening between the screw rod and the nut in the threaded fastener and making it easy to disassemble and replace the nut.

In order to solve the above technical problems, an embodiment of the present disclosure provides a threaded fastening structure for fastening a pretensioner, including: a bolt whose screw rod penetrates the pretensioner and partially protrudes from the pretensioner; a first lock nut , used for threaded connection with the part of the screw rod protruding from the pretensioner, which includes: a first part and a second part coaxially arranged with the bolt, when the first lock nut is connected to the screw rod, the first part is compared with the second part Close to the pretensioner; and the second lock nut, the middle part has a through hole extending along its axial direction and can be penetrated by the screw rod, and the hole wall near the first end of the through hole is provided with a threaded part for threaded connection with the second part , the part in the through hole and between the threaded part and its second end is provided with a fastening washer, when the first lock nut and the second lock nut are locked, the fastening washer is plastically deformed and compressed The screw rod is used to limit the relative position of the first lock nut and the bolt; wherein, the first end and the second end are opposite ends of the second lock nut in the axial direction.

In some embodiments, the screw fastening structure further includes: a limiting part, built in the end of the through hole close to the second end, the limiting part has a circular cross-section and is arranged coaxially with the through hole, and the fastening gasket is located on the limiting part. The position portion faces the end face of the first end, and the inner diameter of the limiting portion is adapted to the outer diameter of the screw.

In some embodiments, the section of the fastening gasket is circular, and its outer diameter fits the inner diameter of the through hole.

In some embodiments, the fastening gasket has a fracture on one side in the circumferential direction, and the width of the fracture is not greater than the thickness of the fastening gasket.

In some embodiments, an undercut groove is provided between the threaded part and the limiting part, the inner diameter of the undercut groove is larger than the diameter of the through hole, and the dimension of the undercut groove in its axial direction is smaller than that of the fastening gasket in its axial direction. on the thickness.

In some embodiments, a chamfer is provided at the end of the limiting portion near the undercut, and the diameter of the largest diameter of the chamfer is larger than the outer diameter of the fastening gasket and smaller than the inner diameter of the undercut.

In some embodiments, the cross-sectional outer contour of the second part is circular, and the peripheral side of the second part is provided with an external thread adapted to the threaded part along the axial direction of the second part, and the second lock nut passes through the threaded part. And external thread threaded connection.

In some embodiments, the cross-sectional outer contour of the first part is hexagonal, and the diameter of the inscribed circle thereof is larger than the outer diameter of the second part.

In some embodiments, the dimension of the second portion in the axial direction is greater than the length of the threaded portion in the axial direction.

In some embodiments, the fastening gasket is made of a metal material with predetermined plasticity and predetermined ductility, and its material hardness is lower than that of the first locking nut and the second locking nut.

Through the above technical solution, the threaded fastening structure provided by the present disclosure passes through the pretensioning part through the bolt, and the screw part of the bolt protrudes from the pretensioning part, and the first lock nut protrudes out of the pretensioning part through the thread and the bolt. The screw part of the screw is threaded, so that the end of the first part of the first lock nut is attached to the surface of the pretensioner, the second lock nut is threaded to the second part of the first lock nut, and the second lock The inside of the lock nut is provided with a fastening washer. When the second lock nut is locked with the first lock nut, the fastening washer will Extruded by the first lock nut and the second lock nut to produce plastic deformation and close to the extrusion screw to limit the relative position of the first lock nut and the bolt, when the first lock nut and the second lock nut need to be disassembled When tightening the nut, since the plastic deformation produced by the fastening gasket is irreversible, it is only necessary to reversely twist the second lock nut with force, and the gap between the second lock nut and the first lock nut can be made through the deformed fastening washer. The threaded connection between them is disconnected, and the deformed fastening gasket can be knocked off from the bolt by a tool, and then the first lock nut is disassembled from the bolt. The threaded fastening structure proposed in the present application can effectively solve the problem of anti-loosening between nuts and bolts in threaded fasteners, and facilitate the disassembly and replacement of nuts.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only These are some embodiments of the present disclosure. Those skilled in the art can also obtain other drawings based on these drawings without creative work.

FIG. 1 is a schematic cross-sectional structure diagram of a threaded fastening structure disclosed in an embodiment of the present disclosure;

Fig. 2 is a schematic isometric structural view of the pre-installation of the first lock nut and the second lock nut disclosed in the embodiment of the present disclosure;

Fig. 3 is a schematic cross-sectional structural view of the pre-installation of the first lock nut and the second lock nut disclosed in the embodiment of the present disclosure;

Fig. 4 is a schematic cross-sectional structure diagram of a first lock nut disclosed in an embodiment of the present disclosure;

Fig. 5 is a schematic cross-sectional structure diagram of a second lock nut disclosed in an embodiment of the present disclosure;

Fig. 6 is a schematic cross-sectional structure diagram of a fastening gasket disclosed in an embodiment of the present disclosure.

Explanation of reference signs:

1. Pretensioner; 2. Bolt; 201. Screw; 3. First lock nut; 301. First part; 302. Second part; 303. External thread; 4. Second lock nut; 401. Through hole ; 401a, threaded part; 402, first end; 403, second end; 404, undercut; 5, fastening gasket; 501, fracture;

Detailed ways

Embodiments of the present disclosure will be further described in detail below in conjunction with the accompanying drawings and embodiments. The detailed description and accompanying drawings of the following embodiments are used to illustrate the principles of the present disclosure, but cannot be used to limit the scope of the present disclosure. The present disclosure can be implemented in many different forms, and is not limited to the specific embodiments disclosed herein. Rather, it includes all technical solutions falling within the scope of the claims.

These embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. It should be noted that unless specifically stated otherwise, the relative arrangement of parts and steps, the composition of materials, numerical expressions and numerical values set forth in these embodiments should be interpreted as illustrative only and not as limiting.

It should be noted that, in the description of the present disclosure, unless otherwise specified, the meaning of "plurality" is greater than or equal to two; the terms "upper", "lower", "left", "right", "inside" The orientation or positional relationship indicated by , "outside" and so on are only for the convenience of describing the present disclosure and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of this disclosure. When the absolute position of the described object changes, the relative position relationship may also change accordingly.

In addition, "first", "second" and similar words used in the present disclosure do not indicate any order, quantity or importance, but are only used to distinguish different parts. "Vertical" is not strictly vertical, but within the allowable range of error. "Parallel" is not strictly parallel, but within the allowable range of error. Words like "comprising" or "comprising" mean that the elements preceding the word cover the elements listed after the word, and do not exclude the possibility of also covering other elements.

It should also be noted that, in the description of the present disclosure, unless otherwise clearly stipulated and limited, the terms "installation", "connection" and "connection" should be interpreted in a broad sense, for example, it may be a fixed connection or a flexible connection. Disassembled connection, or integral connection; it can be directly connected or indirectly connected through an intermediary. Those of ordinary skill in the art can understand the specific meanings of the above terms in the present disclosure according to specific situations. When it is described that a specific device is located between a first device and a second device, there may or may not be an intervening device between the specific device and the first device or the second device.

All terms used in the present disclosure have the same meaning as understood by those of ordinary skill in the art to which the present disclosure belongs, unless otherwise specifically defined. It should also be understood that terms defined in, for example, general-purpose dictionaries should be interpreted as having meanings consistent with their meanings in the context of the relevant technology, and should not be interpreted in idealized or extremely formalized meanings, unless explicitly stated herein Defined like this.

Techniques, methods and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, techniques, methods and devices should be considered part of the description.

Referring to accompanying drawings 1 to 6, the embodiment of the utility model proposes a threaded fastening structure for fastening the pretensioning part 1, the threaded fastening structure includes: a bolt 2, the screw rod 201 of which runs through the pretensioning part 1 And part protrudes from the pre-tensioning part 1; the first lock nut 3 is used for screw connection with the part of the screw rod 201 protruding from the pre-tensioning part 1, which includes: the first part 301 and the second part coaxially arranged with the bolt 2 Part 302, when the first lock nut 3 is connected to the screw rod 201, the first part 301 is closer to the pretensioner 1 than the second part 302; The through hole 401 through which the screw 201 passes, the hole wall of the through hole 401 close to the first end 402 is provided with a threaded part 401a for threaded connection with the second part 302, the through hole 401 is located between the threaded part 401a and its second end 403 The part between is provided with a fastening washer 5, when the first lock nut 3 and the second lock nut 4 are locked, the fastening washer 5 produces plastic deformation and compresses the screw rod 201 to limit the first lock nut 3 and the relative position of the bolt 2; wherein, the first end 402 and the second end 403 are the opposite ends of the second locking nut 4 in its axial direction.

Specifically, the threaded fastening structure proposed in the embodiment of the present disclosure is used to lock and fix the pretensioning part 1. The pretensioning part 1 can be specifically two flat plates to be connected and fixed against each other. The pretensioning part 1 has The mounting hole adapted to the threaded fastening structure, the threaded fastening structure specifically includes: a bolt 2, a first lock nut 3 and a second lock nut 4, the nut part of the bolt 2 is located on one side of the pretensioner , the screw 201 passes through the installation hole on the pretensioner 1 and partially protrudes from the other side of the pretensioner 1, the first lock nut 3 is threadedly connected with the screw 201 and the first part 301 of the first lock nut 3 is close to the pretensioner Tightening part 1, the middle part of the second locking nut 4 has a through hole 401 that extends axially and can be penetrated by the screw rod 201, and the hole wall of the through hole 401 near the first end 402 of the second locking nut 4 is provided with a The threaded part 401a threadedly connected with the second part 302 of the first lock nut 3, the second lock nut 4 is threadedly connected with the second part 302 of the first lock nut 3 through the threaded part 401a thereon, the through hole 401 A fastening washer 5 is provided in the part between the threaded part 401a and the second end 403 of the second lock nut 4. When the first lock nut 3 and the second lock nut 4 are locked, the thread Under the action of the connection, the fastening washer 5 is squeezed by the first lock nut 3 and the second lock nut 4 and undergoes plastic deformation to compress the screw rod 201 to limit the relative position of the first lock nut 3 and the bolt 2 .

According to the above list, the screw fastening structure proposed by the embodiment of the present disclosure penetrates the pretensioner 1 through the screw rod 201 of the bolt 2, and the threaded connection between the first lock nut 3 and the screw rod 201 makes the first lock nut 3 The first part 301 is close to the pretensioning part 1, so as to realize the fastening installation of the pretensioning part 1, the threaded part 401a provided in the through hole 401 of the second locking nut 4 is threaded with the second part 302 of the first locking nut 3 connection, when the first lock nut 3 and the second lock nut 4 are locked, the fastening gasket 5 provided in the through hole 401 produces plastic deformation and compresses the screw rod 201 to limit the first lock nut 3 and the bolt 2, so as to prevent the first lock nut 3 from loosening and detaching from the screw rod 201. The thread fastening structure proposed in the embodiment of the present disclosure can effectively prevent the first lock nut 3 from loosening due to long-term vibration.

In some embodiments, referring to accompanying drawings 3 and 5, in specific implementation, the threaded fastening structure further includes: a limiting part 6, built into the end of the through hole 401 close to the second end 403, the limiting part 6 has a circular cross-section and is coaxial with the through hole 401 . The fastening washer 5 is located on the end surface of the stopper 6 facing the first end 402 . The inner diameter of the stopper 6 matches the outer diameter of the screw 201 .

Specifically, in order to realize that the fastening gasket 5 can be built into the through hole 401 and the fastening gasket 5 will not disengage from the through hole 401, in the technical solution adopted by the utility model, the threaded fastening structure is also provided with a limiting part 6. In a specific embodiment, the limiting part 6 can be integrated with the second lock nut 4, the limiting part 6 is arranged at the end of the through hole 401 close to the second end 403, and the cross section of the limiting part 6 is ring-shaped And coaxial with the through hole 401, the inner diameter of the stopper 6 is adapted to the outer diameter of the screw 201. When the fastening gasket 5 is built in the through hole 401, the stopper 6 can prevent the fastening washer from 5 is disengaged from the through hole 401, and the screw 201 can pass through the inner hole of the fastening washer 5 through the through hole 401, and then pass through the entire second locking nut 4 through the inner hole of the limiting part 6.

In some embodiments, referring to FIG. 6 , in a specific implementation, the cross section of the fastening gasket 5 is circular, and its outer diameter is adapted to the inner diameter of the through hole 401 .

Specifically, in order to realize that the fastening gasket 5 can be built into the through hole 401, in the technical solution adopted by the utility model, the section of the fastening gasket 5 is circular, and its outer diameter is the same as the inner diameter of the through hole 401. The dimensions are adapted so that the fastening washer 5 can be built into the through hole 401 and placed coaxially with the through hole 401 .

In some embodiments, referring to FIG. 6 , in practice, the fastening gasket 5 has a fracture 501 on one side of its circumferential direction, and the width of the fracture 501 is not greater than the thickness of the fastening gasket 5 .

Specifically, in order to realize that the fastening gasket 5 is easy to produce plastic deformation due to extrusion, in the technical solution adopted by the utility model, the fastening gasket 5 is provided with a fracture 501 on one side of its circumferential direction, and the width of the fracture 501 is different. When the thickness of the fastening washer 5 is greater than that of the fastening washer 5 , when the fastening washer 5 is simultaneously squeezed by the first lock nut 3 and the second lock nut 4 , the fracture 501 can make the fastening washer more prone to plastic deformation.

In some embodiments, referring to accompanying drawing 1, accompanying drawing 3 and accompanying drawing 5, in specific implementation, there is an undercut 404 between the threaded part 401a and the limiting part 6, and the inner diameter of the undercut 404 is larger than that of the normal The diameter of the hole 401 and the size of the undercut 404 in the axial direction are smaller than the thickness of the fastening gasket 5 in the axial direction.

Specifically, in order to realize that the fastening gasket 5 can prevent the second lock nut 4 from loosening after plastic deformation, in the technical solution adopted by the utility model, a setback is provided between the threaded part 401a and the limiting part 6. The inner diameter of the knife groove 404 and the relief groove 404 is larger than the aperture of the through hole 401, and the size of the relief groove 404 in the axial direction is smaller than the thickness of the fastening gasket 5 in the axial direction. When the fastening gasket 5 undergoes plastic When deformed, part of the deformed fastening gasket 5 will be squeezed into the relief groove 6 to limit the relative position of the first lock nut 3 and the second lock nut 4, thereby effectively preventing the second lock nut from 4 Loose phenomenon occurs.

In some embodiments, referring to accompanying drawings 1 , 3 and 5 , in specific implementation, a chamfer 601 is provided at the end of the limiting portion 6 near the undercut 404 , and the chamfer 601 has the largest diameter The diameter is larger than the outer diameter of the fastening gasket 5 and smaller than the inner diameter of the undercut 404 .

Specifically, in order to realize that after the fastening gasket 5 is squeezed by the first lock nut 3 and the second lock nut 4 to produce plastic deformation, a part of it is easy to be squeezed into the undercut groove 404, the utility model adopts In the technical solution, the limit part 6 is provided with a chamfer 601 near the end of the undercut 404 , and the diameter of the largest diameter of the chamfer 601 is larger than the outer diameter of the fastening gasket 5 and smaller than that of the undercut 404 . Inner diameter size, when the first lock nut 3 and the second lock nut 4 squeeze the fastening gasket 5 and make it plastically deformed, because of the guiding effect of the chamfer 601, the plastically deformed fastening gasket 5 easier to enter in the undercut groove 404.

In some embodiments, referring to accompanying drawings 1 to 5, in specific implementation, the cross-sectional outer contour of the second part 302 is circular, and the circumferential side of the second part 302 is provided along the axial direction of the second part 302 The external thread 303 adapted to the threaded portion 401a, the second locking nut 4 is threadedly connected to the external thread 303 through the threaded portion 401a.

Specifically, in order to realize the threaded connection between the first lock nut 3 and the second lock nut 4, in the technical solution adopted by the utility model, the cross-sectional outer contour of the second part 302 of the first lock nut 3 is a circle shape, and the circumferential side of the second part 302 of the first lock nut 3 is provided with an external thread 303 adapted to the threaded part 401a of the second lock nut 4 along the axis direction of the second part 302, and the second lock nut 4 can be threadedly connected with the first locking nut 3 through the threaded fit between the threaded part 401a and the external thread 303.

In some embodiments, referring to FIG. 1 to FIG. 5 , in specific implementation, the cross-sectional outer contour of the first part 301 is hexagonal, and the diameter of the inscribed circle thereof is larger than the outer diameter of the second part 302 .

Specifically, in order to realize that the first lock nut 3 is easy to disassemble, in the technical solution adopted by the utility model, the cross-sectional outer contour of the first part 301 of the first lock nut 3 is hexagonal, and the diameter of the inscribed circle is larger than The size of the outer diameter of the second part 302 allows the operator to install and disassemble the first lock nut 3 through the first part 301 of the first lock nut 3 by using an external hexagonal wrench.

In some embodiments, referring to FIG. 1 to FIG. 5 , in a specific implementation, the dimension of the second portion 302 in the axial direction is greater than the length of the threaded portion 401 a in the axial direction.

Specifically, in order to realize that the first lock nut 3 and the second lock nut 4 can fully squeeze the fastening gasket 5 to cause plastic deformation, in the technical solution adopted by the utility model, the first lock nut 3 The size of the second part 302 in the axial direction is greater than the length of the threaded part 401a in the second lock nut 4 in the axial direction, so that the external thread 303 on the second part 302 of the first lock nut 3 can completely pass through the second lock nut 3. The threaded portion 401a of the two locking nuts 4 enters into the through hole 401 and can fully squeeze the fastening washer 5 so that the fastening washer 5 is fully deformed.

In some embodiments, in the specific implementation, in the technical solution adopted by the utility model, the fastening gasket 5 is made of a metal material with preset plasticity and preset ductility, and its material hardness is lower than that of the first lock The material hardness of the lock nut 3 and the second lock nut 4.

Specifically, in order to realize that the first lock nut 3 and the second lock nut 4 can plastically deform the fastening gasket 5 through extrusion, in the technical solution adopted by the utility model, the fastening gasket 5 adopts a preset It is made of metal material with plasticity and preset ductility, and its material hardness is lower than that of the first lock nut 3 and the second lock nut 4. In a specific embodiment, the fastening gasket 5 can be made of brass material, the first lock nut 3 and the second lock nut 4 can be made of stainless steel material or carbon steel material, so that the material hardness of the first lock nut 3 and the second lock nut 4 is higher than that of fastening For the washer 5, when the first lock nut 3 and the second lock nut 4 press the fastening washer 5 through the threaded connection, the fastening washer 5 can be plastically deformed due to the hardness of the material.

So far, the embodiments of the present disclosure have been described in detail. Certain details known in the art have not been described in order to avoid obscuring the concept of the present disclosure. Based on the above description, those skilled in the art can fully understand how to implement the technical solutions disclosed herein.

Although some specific embodiments of the present disclosure have been described in detail through examples, those skilled in the art should understand that the above examples are for illustration only, rather than limiting the scope of the present disclosure. Those skilled in the art should understand that the above embodiments can be modified or some technical features can be equivalently replaced without departing from the scope and spirit of the present disclosure. In particular, as long as there is no structural conflict, the technical features mentioned in the various embodiments can be combined in any manner.

Claims (10)

1. A screw thread fastening structure for fastening a pretensioner (1), characterized by comprising:

a bolt (2) having a threaded shaft (201) which penetrates the pre-tightening member (1) and protrudes partially from the pre-tightening member (1);

a first lock nut (3) for threaded connection with a portion of the screw (201) protruding from the pretensioner (1), comprising: a first portion (301) and a second portion (302) coaxially arranged with the bolt (2), the first portion (301) being closer to the pretensioner (1) than the second portion (302) when the first lock nut (3) is connected with the screw (201); and

a second lock nut (4) having a through hole (401) extending along an axial direction thereof and through which the screw (201) passes, a threaded portion (401 a) for threaded connection with the second portion (302) being provided on a hole wall of the through hole (401) near the first end (402), a tightening washer (5) being provided in the through hole (401) at a portion between the threaded portion (401 a) and the second end (403) thereof, the tightening washer (5) plastically deforming and compressing the screw (201) when the first lock nut (3) and the second lock nut (4) are locked to restrict a relative position of the first lock nut (3) and the screw (2);

wherein the first end (402) and the second end (403) are opposite ends of the second lock nut (4) in the axial direction thereof.

2. The screw fastening structure according to claim 1, further comprising:

the limiting part (6) is arranged in the end part of the through hole (401) close to the second end (403), the cross section of the limiting part (6) is annular and is coaxially arranged with the through hole (401), the fastening gasket (5) is positioned on the end face of the limiting part (6) facing the first end (402), and the inner diameter size of the limiting part (6) is matched with the outer diameter size of the screw (201).

3. The screw fastening structure according to claim 2, wherein,

the section of the fastening gasket (5) is annular, and the outer diameter size of the fastening gasket is matched with the inner diameter size of the through hole (401).

4. A screw fastening structure according to claim 3, wherein,

a fracture (501) is formed in one side of the fastening gasket (5) in the circumferential direction, and the width dimension of the fracture (501) is not larger than the thickness dimension of the fastening gasket (5).

5. A screw fastening structure according to claim 3, wherein,

a clearance groove (404) is formed between the threaded part (401 a) and the limiting part (6), the inner diameter size of the clearance groove (404) is larger than the aperture of the through hole (401), and the size of the clearance groove (404) in the axial direction is smaller than the thickness of the fastening gasket (5) in the axial direction.

6. The screw-thread fastening structure according to claim 5, wherein,

the end part of the limiting part (6) close to the tool retracting groove (404) is provided with a chamfer (601), and the diameter size of the largest diameter part of the chamfer (601) is larger than the outer diameter size of the fastening gasket (5) and smaller than the inner diameter size of the tool retracting groove (404).

7. The screw fastening structure according to claim 1, wherein,

the cross-section outline of second part (302) is circular, just the circumference side of second part (302) is followed the axis direction of second part is seted up with external screw thread (303) of screw thread portion (401 a) adaptation, second lock nut (4) pass through screw thread portion (401 a) with external screw thread (303) threaded connection.

8. The thread tightening structure according to claim 7, wherein,

the first portion (301) has a hexagonal cross-sectional outer profile with an inscribed circle having a diameter dimension greater than an outer diameter dimension of the second portion (302).

9. The screw fastening structure according to claim 1, wherein,

the dimension of the second portion (302) in the axial direction is larger than the length of the threaded portion (401 a) in the axial direction thereof.

10. The screw fastening structure according to claim 1, wherein,

the fastening gasket (5) is made of a metal material with preset plasticity and preset ductility, and the hardness of the metal material is lower than that of the first locking nut (3) and the second locking nut (4).