A high preload torsion shear type high strength single-side self-tightening bolt and use method

Abstract

The present invention relates to a high-preload torsion shear type high-strength single-sided self-tightening bolt and a method for using the bolt. The structure comprises a bolt body, a threaded sleeve is sleeved on the bolt rod of the bolt body, the two ends of the bolt rod are respectively a bolt head and a plum blossom head, a nut is installed on the bolt rod close to the plum blossom head through a thread, a first sleeve, a second sleeve, a third sleeve and a shear washer are sleeved on the bolt rod in sequence from the bolt head to the plum blossom head, an annular circular arc groove is provided on the inner circumferential wall of the first sleeve; the threaded sleeve is located in the third sleeve, when the plum blossom head of the bolt body is subjected to an axial force, the annular circular arc groove is deformed outwardly, the threaded sleeve may be positionally offset relative to the third sleeve, and at the same time, the threaded sleeve and the third sleeve exert pressure on the shear washer, and the third sleeve enters the inner cavity of the shear washer; the present invention can simply and quickly realize single-sided tightening operation, and the preload force and bearing capacity can meet the requirements of connection tightening in the steel structure design standard.

Description

Technical Field

[0001] The invention relates to a high-pretightening force torsion shear type high-strength single-side self-tightening bolt and a use method thereof, belonging to the technical field of civil engineering and mechanical connection and fastening. Background Art

[0002] At present, in the fields of civil engineering and mechanical installation, the installation demand for the connection and tightening of structural parts is very huge; at present, when the traditional bolts are used for connection and tightening operations, the staff needs to work from both sides of the connected parts, that is, insert the bolt with the nut from one side of the bolt hole, and then tighten the nut with a tool on the other side. The above connection and tightening method is simple in structure, easy to operate, and has good bearing capacity, but it is limited to the connection of open section components. When the operation space on the other side is limited, this commonly used bolt and nut connection and tightening method cannot be used. For example, in steel pipe structures (square steel pipes and round steel pipes) and steel pipe concrete structures, column-to-column splicing, pipe truss reinforcement, beam-column node assembly connection and other installation scenarios are often involved. Since the cross-section of the steel pipe is a closed cross-section, it cannot be operated on both sides at the same time, and can only be operated on one side for connection and installation, so traditional bolts and nuts cannot be used for connection and tightening.

[0003] However, there are few devices for single-sided connection bolts of steel structures at home and abroad, and they have disadvantages such as complex operation, few installation tools, and insufficient bearing capacity. Therefore, there is an urgent need for a new type of bolt that can achieve single-sided self-tightening. Summary of the invention

[0004] The present invention provides a high-preload torsion shear type high-strength single-side self-tightening bolt and a use method thereof, which can simply and quickly realize single-side tightening operation, and the preload force and bearing capacity can meet the connection and tightening requirements in the steel structure design standard.

[0005] The technical solution adopted by the present invention to solve the technical problem is:

[0006] A high pre-tightening force torsion shear type high-strength single-side self-tightening bolt comprises a bolt body, a threaded sleeve is sleeved on a bolt rod of the bolt body, and the threaded sleeve is meshed with a thread of the bolt rod;

[0007] The two ends of the bolt rod are respectively a bolt head and a plum head, the bolt head protrudes from the bolt rod, a nut is installed on the bolt rod close to the plum head through a thread, a first sleeve, a second sleeve, a third sleeve and a shear washer are sequentially sleeved on the bolt rod from the bolt head to the plum head, and an annular arc groove is provided on the inner circumferential wall of the first sleeve;

[0008] The threaded sleeve is located in the third sleeve. When the plum blossom head of the bolt body is subjected to axial force, the annular arc groove is deformed outward, and the threaded sleeve may be offset relative to the third sleeve. At the same time, the threaded sleeve and the third sleeve exert pressure on the shear washer, and the third sleeve enters the inner cavity of the shear washer.

[0009] As a further preferred embodiment of the present invention, an end surface of the first sleeve adjacent to the bolt head is in close contact with the protruding portion of the bolt head, and the other end surface of the first sleeve is in close contact with an end surface of the second sleeve;

[0010] A sleeve step is provided at the opening of the other end of the second sleeve, one end of the third sleeve is engaged with the other end of the second sleeve through the sleeve step, and the inner diameter of the third sleeve is greater than the inner diameter of the second sleeve;

[0011] The outer diameter of the threaded sleeve is equal to the inner diameter of the third sleeve, and the end surface of one end of the threaded sleeve is in contact with the other end surface of the second sleeve;

[0012] As a further preferred embodiment of the present invention, the inner diameter of the third sleeve is equal to the outer diameter of the sleeve step of the second sleeve;

[0013] As a further preferred embodiment of the present invention, the inner cavity of the shear washer is a hollow cavity, a seat is arranged at one end of the shear washer, the seat abuts against the other end of the third sleeve, and the threaded sleeve and the third sleeve can shear off the seat when applying pressure to the shear washer, so that the third sleeve enters the inner cavity of the shear washer;

[0014] As a further preferred embodiment of the present invention, a groove is further provided at one end of the pedestal on which the shear washer is arranged, the other end of the third sleeve is embedded in the groove and abuts against the pedestal, and a first washer step is further provided in the groove;

[0015] A second washer step is provided at the other end of the shear washer;

[0016] As a further preferred embodiment of the present invention, a gasket is arranged between the other end of the shear washer and the nut;

[0017] As a further preferred embodiment of the present invention, the length of the first sleeve is greater than the length of the second sleeve and the third sleeve;

[0018] The sum of the lengths of the second sleeve and the third sleeve matches the thickness of the component;

[0019] As a further preferred embodiment of the present invention, the width of the threaded sleeve is greater than or equal to twice the thread distance;

[0020] As a further preferred embodiment of the present invention, the first sleeve is made of a material having a yield strength in the range of 200MPa-300MPa and an elongation of at least 40%;

[0021] The second sleeve and the third sleeve are made of materials with a yield strength greater than 900MPa;

[0022] The method for using the high preload torsion shear type high strength single-side self-tightening bolt specifically includes the following steps:

[0023] The first step is to select the first component and the second component to be fastened, wherein the first component is a closed cross section and one end surface near the second component is operable;

[0024] The second step is to assemble the bolt head, the first sleeve, the second sleeve, the third sleeve, the threaded sleeve, the shear washer, the washer and the nut of the bolt body in sequence, and insert the assembled bolt body into the bolt holes of the first component and the second component, and one end face of the shear washer is closely attached to the outer wall of the second component to achieve accurate positioning;

[0025] The third step is to insert the plum head and nut of the bolt body into the inner sleeve and outer sleeve of the torsion shear type electric wrench respectively, start the torsion shear type electric wrench, rotate the inner sleeve, and tighten the bolt body;

[0026] The annular arc groove on the inner circumferential wall of the first sleeve is deformed under the action of the axial force and squeezes the second sleeve. The annular arc groove is deformed outward to form an enlarged head. At this time, the threaded sleeve moves in the third sleeve toward the shear washer until the other end of the threaded sleeve passes through the groove and contacts the seat of the shear washer.

[0027] Step 4: The torsion shear type electric wrench continues to start, and the threaded sleeve and the third sleeve squeeze the seat of the shear washer to cut off the seat. At this time, the third sleeve moves freely in the cavity of the shear washer to release the axial force of the outer sleeve.

[0028] The fifth step is to continue to start the torsion shear type electric wrench, the enlarged head gradually contacts the inner wall of the first component, and the plum head is cut off. At this time, the preload force of the bolt body is fully transferred to the first component and the second component, and the installation is completed.

[0029] Through the above technical solution, compared with the prior art, the present invention has the following beneficial effects:

[0030] 1. The self-tightening bolt provided by the present invention only needs to be installed on one side, realizing unilateral operation, and is suitable for node connection of steel structures, especially closed-section steel tube concrete;

[0031] 2. The structure provided by the present invention comprises a sleeve, a second sleeve, a third sleeve and a shear washer which are spliced ​​in sequence, which can be adjusted according to the total thickness of the fastened component and can be applied to the connection of steel plates of different models;

[0032] 3. The structure provided by the present invention includes a threaded sleeve, which is used in conjunction with other components to control the amount of compression during the forming stage, thereby improving the stability of the anchor head;

[0033] 4. The structural use method provided by the present invention has relatively small requirements on the size of the bolt holes of the connected components and does not significantly weaken the strength of the connecting parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0035] Figure 1 It is a schematic diagram of the overall structure provided by the present invention;

[0036] Figure 2 It is a schematic diagram of the bolt rod structure provided by the present invention;

[0037] Figure 3 It is a schematic diagram of the first sleeve structure provided by the present invention;

[0038] Figure 4 is a schematic diagram of the structure of a second sleeve provided by the present invention;

[0039] Figure 5 is a schematic diagram of the structure of a third sleeve provided by the present invention;

[0040] Figure 6 It is a schematic diagram of the structure of the threaded sleeve provided by the present invention;

[0041] Figure 7 It is a schematic diagram of the structure of the shear washer provided by the present invention;

[0042] Figure 8 It is a structural schematic diagram of a preferred embodiment provided by the present invention;

[0043] Fig. 9 It is a structural schematic diagram of the deformation of the first sleeve when the preferred embodiment provided by the present invention is implemented;

[0044] Fig.10 It is a schematic diagram of the base of the shear washer after being sheared off when the preferred embodiment provided by the present invention is implemented;

[0045] Fig.11 It is a schematic diagram of the shearing of the plum blossom head after the tightening work is completed in the preferred embodiment provided by the present invention.

[0046] In the figure: 1 is a bolt rod, 1-1 is a bolt head, 1-2 is a plum blossom head, 2 is a first sleeve, 2-1 is an annular arc groove, 3 is a second sleeve, 3-1 is a sleeve step, 4 is a third sleeve, 5 is a threaded sleeve, 5-1 is a threaded sleeve having a thread on the inner side matching the thread of the bolt rod, 6 is a shear washer, 6-1 is a first washer step, 6-2 is a pedestal, 6-3 is a cavity, 6-4 is a second washer step, 7 is a gasket, 8 is a nut, 9 is a first component, 10 is a second component, 11 is an enlarged head, 13 is an inner sleeve, 14 is an outer sleeve, and 15 is an enlarged head gradually contacting the inner wall of the first component. DETAILED DESCRIPTION

[0047] The present invention will now be described in further detail with reference to the accompanying drawings. In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "left side", "right side", "upper part", "lower part", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and "first", "second", etc. do not indicate the importance of the components, and therefore cannot be understood as a limitation on the present invention. The specific dimensions used in this embodiment are only for illustrating the technical solution by example, and do not limit the scope of protection of the present invention.

[0048] In the prior art, the cross-section of steel pipes is mostly a closed cross-section, so it is impossible to operate on both sides at the same time during installation. The present application is to overcome this problem and provide a new type of bolt that can be operated on one side to achieve connection and installation.

[0049] Figure 1 The invention provides a high pre-tightening force torsion shear type high-strength single-side self-tightening bolt, comprising a bolt body, which comprises a bolt rod 1, Figure 2 As shown, a bolt head 1-1 and a plum head 1-2 are respectively connected at both ends of the bolt rod. From the figure, it can be seen that there are the following components: a threaded sleeve 5, a first sleeve 2, a second sleeve 3, a third sleeve 4 and a shear washer 6. The connection relationship between the above components is that a threaded sleeve is sleeved on the bolt rod, the threaded sleeve is meshed with the thread of the bolt rod, the bolt head protrudes from the bolt rod, a nut 8 is installed on the bolt rod close to the plum head through a thread, and the first sleeve, the second sleeve, the third sleeve and the shear washer are sequentially sleeved on the bolt rod from the bolt head to the plum head. An annular arc groove 2-1 is provided on the inner circumferential wall of the first sleeve, and the threaded sleeve is located in the third sleeve;

[0050] There are two important innovations in this application. Figure 3The annular arc groove opened on the inner circumferential wall of the first sleeve shown in the figure is that the threaded sleeve is located in the third sleeve, and the threaded sleeve can be offset relative to the third sleeve; these two innovative points match each other with other components of the present application, that is, when the plum blossom head of the bolt body is subjected to axial force, the annular arc groove is deformed to the outside, and then the threaded sleeve and the third sleeve apply pressure to the shear washer, and the third sleeve enters the inner cavity of the shear washer. The threaded sleeve controls the compression amount of the enlarged head 11 of the first sleeve during the forming stage, thereby improving the stability of the anchor head. At the same time, the third sleeve enters the inner cavity of the shear washer to realize the release of the axial force of the outer sleeve 14 and transfer all the preload force to the connected components.

[0051] Now, the above components are specifically described. The end surface of one end of the first sleeve adjacent to the bolt head is in close contact with the protruding portion of the bolt head, and the other end surface of the first sleeve is in close contact with the end surface of one end of the second sleeve. Figure 4 As shown, a sleeve step 3-1 is provided at the other end opening of the second sleeve. Figure 5 One end of the third sleeve shown is engaged with the other end of the second sleeve through a sleeve step, and the inner diameter of the third sleeve is larger than the inner diameter of the second sleeve. The shear bearing capacity of the entire structure can be enhanced by controlling the position of the third sleeve through the sleeve step. In the preferred embodiment, the inner diameter of the third sleeve is equal to the outer diameter of the sleeve step of the second sleeve; the outer diameter of the threaded sleeve is equal to the inner diameter of the third sleeve, and the end face of one end of the threaded sleeve is fitted with the end face of the other end of the second sleeve. The inner side of the threaded sleeve has a thread 5-1 that matches the thread of the bolt rod. In order to reduce the friction between the threaded sleeve and the third sleeve, molybdenum disulfide lubricant can be coated on the contact surface between the threaded sleeve and the third sleeve. Figure 6 The figure shows the schematic diagram of the structure of the threaded sleeve. Compared with the first sleeve, the second sleeve and the third sleeve, it is found that the width of the threaded sleeve is smaller. Generally, we limit the minimum width of the threaded sleeve to 2 times the thread distance. If it is less than this width, it will affect the insufficient force of the threaded sleeve when applying prestress to the shear washer. The maximum width of the threaded sleeve will not exceed the length of the third sleeve, which can meet the displacement and sliding of the threaded sleeve in the third sleeve and meet the prestress applied to the shear washer. Figure 7It is a structural schematic diagram of a shear washer. The inner cavity of the shear washer is a cavity 6-3. A seat 6-2 is set at one end of the shear washer. A groove is also set at one end of the seat of the shear washer. The other end of the third sleeve is embedded in the groove and abuts against the seat. When the threaded sleeve and the third sleeve apply pressure to the shear washer, the seat can be cut off so that the third sleeve can enter the inner cavity of the shear washer. The purpose of setting the seat is to provide pressure in the stage of the first sleeve forming the enlarged head, and to cut off under the joint action of the threaded sleeve and the third sleeve at the end of the enlarged head forming. The groove is set to facilitate the inner diameter of the cavity of the shear washer to meet the free passage of the third sleeve after the seat is cut off. When the third sleeve moves freely in the cavity, the internal force of the second sleeve and the third sleeve is released when installed and fixed. Through the setting of the shear washer, the preload force of the entire structure can reach the size required by the standards related to steel structures.

[0052] Figure 7 As can be seen from the enlarged structure of the shear washer, a first washer step 6-1 is provided in the groove, and a second washer step 6-4 is provided at the other end of the shear washer. The first washer step is provided to control the position of the shear washer, and the base provides support for the third sleeve to ensure the completion of the shear mechanism. The second washer step is provided to limit the sliding of the third sleeve in the cavity.

[0053] from Figure 8 It can be seen from the embodiments that the length of the first sleeve is greater than that of the second sleeve and the third sleeve. This is because the first sleeve is the first to bear the axial force during the anchoring process. If the length of the first sleeve is not long enough, insufficient strength will occur during the anchoring process. Of course, the length of the first sleeve is based on the preload force of the bolt body during production. The greater the preload force, the longer the first sleeve. The sum of the lengths of the second sleeve and the third sleeve is related to the thickness of the component, such as Figure 8 It can be seen from the illustrated embodiment that the sum of the lengths of the second sleeve and the third sleeve is close to the width of the bolt holes of the first component 9 and the second component 10 .

[0054] The preferred embodiment also has the following details, such as, in order to buffer the pressure, a gasket 7 is arranged between the other end of the shear washer and the nut; the first sleeve is made of an alloy material with a yield strength range of 200MPa-300MPa, and its elongation is at least 40%, that is, it can be made of high-quality carbon structural steel 20Mn, which can effectively improve the strength of the anchor head; the second sleeve and the third sleeve are both made of materials with a yield strength greater than 900MPa.

[0055] Finally, the applicant also provides a method for using the high preload torsion shear type high strength single-side self-tightening bolt, which specifically includes the following steps:

[0056] The first step is to select the first component and the second component to be fastened, wherein the first component is a closed cross section and one end surface near the second component is operable;

[0057] The bolt head, the first sleeve, the second sleeve, the third sleeve, the threaded sleeve, the shear washer, the washer and the nut of the bolt body are assembled in sequence, and the assembled bolt body is inserted into the bolt holes of the first component and the second component, and one end face of the shear washer is closely attached to the outer wall of the second component to achieve accurate positioning;

[0058] The third step is to insert the plum head and nut of the bolt body into the inner sleeve 13 and the outer sleeve of the torsion shear type electric wrench respectively, start the torsion shear type electric wrench, rotate the inner sleeve, and tighten the bolt body;

[0059] The annular arc groove on the inner circumferential wall of the first sleeve is deformed under the action of the axial force and squeezes the second sleeve, and the annular arc groove is deformed outward to form Fig. 9 The enlarged head shown, at this time, the threaded sleeve moves in the third sleeve toward the shear washer until the other end of the threaded sleeve passes through the groove and contacts the seat of the shear washer;

[0060] Step 4: The torsion shear type electric wrench continues to start, and the threaded sleeve and the third sleeve squeeze the seat of the shear washer. Fig.10 As shown, the seat is cut off, and the third sleeve is free to move in the cavity of the shear washer, releasing the axial force of the outer sleeve and the inner sleeve;

[0061] Step 5: Continue to start the torsion shear type electric wrench, and the enlarged head gradually contacts the inner wall of the first component (the state here is Fig.11 Mark 15 in the figure), the plum head is cut off, and the preload force of the bolt body is fully transmitted to the first component and the second component. Fig.11 Installation is complete.

[0062] In summary, the bolt structure provided in this application can be installed using the same installation tools as those used for domestic steel structures, meets the requirements of steel structure design, is suitable for node connections of steel structures, especially closed-section steel tube concrete, and can be widely promoted in actual projects.

[0063] It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as those generally understood by those skilled in the art to which this application belongs. It should also be understood that terms such as those defined in common dictionaries should be understood to have meanings consistent with the meanings in the context of the prior art, and will not be interpreted with idealized or overly formal meanings unless defined as herein.

[0064] The meaning of "and / or" described in this application means that the situations where each exists alone or both exist at the same time are included.

[0065] The term “connection” as used in this application may mean a direct connection between components or an indirect connection between components via other components.

[0066] Based on the above ideal embodiments of the present invention, the relevant staff can make various changes and modifications without departing from the technical concept of the present invention through the above description. The technical scope of the present invention is not limited to the contents of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A high preload torsion shear type high strength single-side self-tightening bolt, characterized by: It comprises a bolt body, a threaded sleeve (5) is sleeved on a bolt rod (1) of the bolt body, and the threaded sleeve (5) is meshed with the thread of the bolt rod (1); The two ends of the bolt rod (1) are respectively a bolt head (1-1) and a plum blossom head (1-2); the bolt head (1-1) protrudes out of the bolt rod (1); a nut (8) is threadedly mounted on the bolt rod (1) near the plum blossom head (1-2); a first sleeve (2), a second sleeve (3), a third sleeve (4) and a shear washer (6) are sequentially sleeved on the bolt rod (1) from the bolt head (1-1) to the plum blossom head (1-2); and an annular arc groove (2-1) is provided on the inner circumferential wall of the first sleeve (2); The threaded sleeve (5) is located inside the third sleeve (4). When the plum blossom head (1-2) of the bolt body is subjected to an axial force, the annular arc groove (2-1) is deformed outwardly, and the threaded sleeve (5) may be displaced relative to the third sleeve (4). At the same time, the threaded sleeve (5) and the third sleeve (4) exert pressure on the shear washer (6), and the third sleeve (4) enters the inner cavity of the shear washer (6). The inner cavity of the shear washer (6) is a hollow cavity (6-3). A seat (6-2) is arranged at one end of the shear washer (6). The seat (6-2) abuts against the other end of the third sleeve (4). When the threaded sleeve (5) and the third sleeve (4) apply pressure to the shear washer (6), the seat (6-2) can be sheared off, so that the third sleeve (4) enters the inner cavity of the shear washer (6). A groove is also provided at one end of the shear washer (6) on which the pedestal (6-2) is arranged, and the other end of the third sleeve (4) is embedded in the groove and abuts against the pedestal (6-2), and a first washer step (6-1) is also provided in the groove; A second washer step (6-4) is provided at the other end of the shear washer (6).

2. The high preload torsion shear type high strength single-side self-tightening bolt according to claim 1, characterized in that: An end surface of the first sleeve (2) adjacent to the bolt head (1-1) is in close contact with a protruding portion of the bolt head (1-1), and the other end surface of the first sleeve (2) is in close contact with an end surface of the second sleeve (3); A sleeve step (3-1) is provided at the opening of the other end of the second sleeve (3); one end of the third sleeve (4) engages with the other end of the second sleeve (3) through the sleeve step (3-1); and the inner diameter of the third sleeve (4) is greater than the inner diameter of the second sleeve (3); The outer diameter of the threaded sleeve (5) is equal to the inner diameter of the third sleeve (4), and one end surface of the threaded sleeve (5) is in contact with the other end surface of the second sleeve (3).

3. The high preload torsion shear type high strength single-side self-tightening bolt according to claim 2, characterized in that: The inner diameter of the third sleeve (4) is equal to the outer diameter of the sleeve step (3-1) of the second sleeve (3).

4. The high preload torsion shear type high strength single-side self-tightening bolt according to claim 1, characterized in that: A gasket (7) is arranged between the other end of the shear washer (6) and the nut (8).

5. The high preload torsion shear type high strength single-side self-tightening bolt according to claim 1, characterized in that: The length of the first sleeve (2) is greater than the length of the second sleeve (3) and the third sleeve (4); The sum of the lengths of the second sleeve (3) and the third sleeve (4) matches the thickness of the component.

6. The high preload torsion shear type high strength single-side self-tightening bolt according to claim 1, characterized in that: The width of the threaded sleeve (5) is greater than or equal to twice the thread distance.

7. The high pre-tightening force torsion shear type high-strength single-side self-tightening bolt according to claim 1, characterized in that: The first sleeve (2) is made of a material having a yield strength in the range of 200 MPa to 300 MPa and an elongation of at least 40%; The second sleeve (3) and the third sleeve (4) are both made of materials with a yield strength greater than 900 MPa.

8. The method for using the high pre-tightening force torsion shear type high-strength single-side self-tightening bolt according to any one of claims 1 to 7, characterized in that: The specific steps include: The first step is to select a first component (9) and a second component (10) to be fastened, wherein the first component (9) is a closed cross-section and an end surface near the second component (10) is operable; The second step is to assemble the bolt head (1-1), the first sleeve (2), the second sleeve (3), the third sleeve (4), the threaded sleeve (5), the shear washer (6), the washer (7) and the nut (8) of the bolt body in sequence, and insert the assembled bolt body into the bolt holes of the first component (9) and the second component (10), with one end face of the shear washer (6) closely attached to the outer wall of the second component (10) to achieve accurate positioning; The third step is to insert the plum head (1-2) and the nut (8) of the bolt body into the inner sleeve (13) and the outer sleeve of the torsion shear type electric wrench respectively, start the torsion shear type electric wrench, rotate the inner sleeve (13), and tighten the bolt body; The annular arc groove (2-1) located on the inner circumferential wall of the first sleeve (2) is deformed under the action of the axial force and squeezes the second sleeve (3). The annular arc groove (2-1) is deformed outwardly to form an enlarged head (11). At this time, the threaded sleeve (5) moves in the third sleeve (4) toward the shear washer (6) until the other end of the threaded sleeve (5) passes through the groove and contacts the base (6-2) of the shear washer (6). In the fourth step, the torsion shear type electric wrench continues to start, the threaded sleeve (5) and the third sleeve (4) squeeze the base (6-2) of the shear washer (6), and the base (6-2) is sheared off. At this time, the third sleeve (4) moves freely in the cavity (6-3) of the shear washer (6), and the axial force of the outer sleeve (14) is released; The fifth step is to continue to start the torsion shear type electric wrench, so that the enlarged head (11) gradually contacts the inner wall of the first component (9), and the plum head (1-2) is sheared off. At this time, the pre-tightening force of the bolt body is completely transmitted to the first component (9) and the second component (10), and the installation is completed.

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