Pre-tightening tool and screwing device

Abstract

The utility model discloses a pre-tightening tool and a screwing device, the pre-tightening tool is applied to a nut, the pre-tightening tool comprises a mounting part and a plurality of pre-tightening parts, the multiple pre-tightening parts are distributed on the mounting part in a circular array mode with the center of the mounting part as the array center, and the distance between the pre-tightening parts and the center of the mounting part is adjustable; the pre-tightening part comprises a connecting piece and a locking piece, the two opposite ends of the connecting piece are detachably connected with the nut and the mounting part respectively, and the end, connected with the nut, of the connecting piece extends out of the mounting part.

Description

TECHNICAL FIELD

[0001] The application relates to the nut assembly technical field, in particular to a pre-tightening tool and a screwing device. BACKGROUND

[0002] In a yaw pitch reducer, the function of the round nut is to adjust the axial clearance of the two bearings of the low-speed shaft and connect the open gear and the lower body and other parts to form a whole part. The round nut plays an important role in the yaw pitch reducer.

[0003] The existing round nut tightening process is divided into two steps: first, manually pre-tighten the round nut to make it rotate into the corresponding threaded part of the open gear, and then use the round nut tightening machine to tighten it.

[0004] However, due to different types of reducers, there are round nuts of various specifications on the assembly site, and the round nut tightening machine needs to be adjusted to adapt to round nuts of different specifications, which not only reduces work efficiency, but also increases labor intensity and makes it difficult to ensure production progress.

[0005] Therefore, it is necessary to provide a new technical solution to solve the technical problem of the adaptability of round nuts of different specifications to the round nut tightening machine. INVENTION CONTENTS

[0006] One object of the application is to provide a new technical solution of a pre-tightening tool.

[0007] According to a first aspect of the application, a pre-tightening tool and a screwing device are provided, the pre-tightening tool being applied to a nut, the pre-tightening tool comprising a mounting part and a pre-tightening part, a plurality of pre-tightening parts being distributed in a circular array on the mounting part with the center of the mounting part as the array center, and the distance between the pre-tightening part and the center of the mounting part being adjustable; the pre-tightening part comprises a connecting piece and a locking piece, the opposite ends of the connecting piece are respectively detachably connected with the nut and the mounting part, and one end of the connecting piece connected with the nut protrudes out of the mounting part.

[0008] Optionally, the connecting piece has oppositely arranged first and second ends, the first end is detachably connected with the locking piece, and the second end has a protruding part, and the protruding part is connected with the nut.

[0009] Optionally, one side of the protruding part is connected with the second end, and the diameter of the protruding part gradually decreases from one side of the connecting piece towards the protruding part.

[0010] Optionally, the mounting part has an adjusting hole, the adjusting hole is opened along the radial direction of the mounting part, one end of the connecting piece passes through the adjusting hole, and the other end is detachably connected with the locking piece.

[0011] Optionally, a reinforcing member is sleeved on the connecting member, and the reinforcing member is located between the locking member and the mounting portion.

[0012] Optionally, the reinforcing member comprises a flat pad, the flat pad is sleeved on an end of the connecting member protruding from the adjusting hole, and the flat pad is located between the locking member and the adjusting hole.

[0013] Optionally, the reinforcing member comprises an elastic pad, the elastic pad is sleeved on an end of the connecting member penetrating through the adjusting hole, and the elastic pad is located between the mounting portion and the locking member, and the elastic pad is capable of elastically deforming along the axial direction of the connecting member.

[0014] Optionally, a knob is arranged on the mounting portion, and the knob is arranged at the axial center of the mounting portion.

[0015] According to a second aspect of the present application, a screwing device is provided, which comprises a nut and the pre-tightening tool as described above.

[0016] Optionally, the nut is provided with a plurality of limiting grooves, the limiting grooves are uniformly distributed on the outer circumferential surface of the nut, in the state that the nut is connected with the pre-tightening tool, the limiting grooves and the connecting member form a limiting fit in the radial direction, and the second end of the connecting member and the nut form a limiting fit in the axial direction.

[0017] In the embodiments of the present application, the center distance between the pre-tightening portion and the mounting portion is adjustable, so that the diameter size of the pre-tightening portion can be adjusted, thereby adapting to different sizes of the nut to be screwed or loosened, effectively improving the adaptability of the pre-tightening tool, and the connecting member of the pre-tightening portion is detachably connected with the locking member and the mounting portion, which not only facilitates the adjustment of the diameter size of the pre-tightening portion to adapt to different sizes of the nut, but also facilitates the replacement of the parts of the pre-tightening tool, thereby reducing the labor intensity of manually screwing or loosening the nut and improving the work efficiency.

[0018] Other features and advantages of the present application will become apparent from the following detailed description of exemplary embodiments thereof, taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0019] The accompanying drawings incorporated in and forming a part of the specification, illustrate embodiments of the present application and, together with the description, serve to explain the principles of the application.

[0020] Figure 1 is a structural schematic diagram of the pre-tightening tool in the embodiments of the present application;

[0021] Figure 2 is a top view of the pre-tightening tool in the embodiments of the present application;

[0022] Figure 3is a front view of a pre-tightening tool in the embodiments of the present application;

[0023] Figure 4 is a structural schematic view of the pre-tightening tool and the nut in the embodiments of the present application.

[0024] Legend of reference signs:

[0025] 1 - mounting portion; 11 - adjusting hole; 12 - knob;

[0026] 2 - pre-tightening portion; 21 - connecting piece; 211 - first end; 212 - second end; 213 - protruding portion; 214 - flat washer; 215 - elastic washer; 22 - locking piece;

[0027] 3 - nut; 31 - limiting groove. DETAILED DESCRIPTION

[0028] Various exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. It should be noted that the relative arrangement of components and steps, numerical expressions, and numerical values set forth in these embodiments are not limiting to the scope of the present application unless specifically stated otherwise.

[0029] The following description of at least one exemplary embodiment is merely exemplary in nature and is in no way intended to limit the application or its application or uses.

[0030] Techniques, methods, and devices known to those of ordinary skill in the relevant art can not be discussed in detail herein. However, where appropriate, techniques, methods, and devices should be considered part of the description of the present application.

[0031] In all of the examples shown and discussed herein, any specific values should be interpreted as merely exemplary and not as a limitation. Thus, other examples of the exemplary embodiments can have different values.

[0032] It should be noted that like reference numerals and letters refer to like items in the several views of the drawings, and as such, further discussion of them is not necessary in the subsequent drawings.

[0033] According to one embodiment of the present application, a pre-tightening tool is provided, which is applied to a nut 3. The pre-tightening tool comprises a mounting portion 1 and a pre-tightening portion 2, a plurality of the pre-tightening portions 2 are distributed in a circular array on the mounting portion 1 with the center of the mounting portion 1 as the array center, and the distance of the pre-tightening portion 2 from the center of the mounting portion 1 is adjustable; the pre-tightening portion 2 comprises a connecting piece 21 and a locking piece 22, the opposite ends of the connecting piece 21 are respectively detachably connected with the nut 3 and the mounting portion 1, and the end of the connecting piece 21 connected with the nut 3 protrudes out of the mounting portion 1.

[0034] AsFigures 1 to 4 As shown, this pre-tightening fixture is used to tighten or loosen a round nut 3. The pre-tightening fixture includes a mounting part 1 and a pre-tightening part 2. The mounting part 1 is a circular plate. The pre-tightening parts 2 are disposed on the mounting part 1, and multiple pre-tightening parts 2 are evenly distributed along the circumferential direction of the mounting part 1. For example, as... Figures 1 to 4 As shown, the three pre-tightening parts 2 are set at equal angles on the mounting part 1.

[0035] Of course, the pre-tightening fixture in this embodiment is not limited to the structure described above, and those skilled in the art can make its own configuration according to actual needs. For example, the mounting part 1 can also be a rectangular plate, and the pre-tightening part 2 can be a gripper with gripping and releasing functions located at the bottom edge of the mounting part 1.

[0036] Both the mounting part 1 and the pre-tightening part 2 are made of 45 steel, and the surface treatment adopts the "quenching + tempering" heat treatment process. 45 steel has high strength and plasticity, and is not easily worn. The surface is further tempered, which greatly improves the strength of the pre-tightening fixture and effectively extends its service life.

[0037] like Figures 1 to 4 As shown, the preload 2 is provided on the mounting part 1, and the distance between the preload 2 and the center of the mounting part 1 is adjustable, meaning that the preload 2 can move radially along the mounting part 1. By providing multiple preload 2s on the mounting part 1, and ensuring that these multiple preload 2s can move radially along the mounting part 1, the diameter of the preload 2s in the preload fixture is adjustable, thereby adapting to nuts 3 of different diameters and improving the adaptability of the preload fixture.

[0038] Of course, the pre-tightening device in this embodiment is not limited to the functions described above, and those skilled in the art can configure it according to actual needs. For example, the pre-tightening fixture can also tighten or loosen a nut 3 with a polygonal outer circumference.

[0039] The pre-tightening part 2 includes a connector 21 and a locking member 22. The connector 21 is cylindrical. One end of the connector 21 extends out of the mounting part 1 and connects to the locking member 22, which is sleeved on that end of the connector 21. The end of the connector 21 away from the locking member 22 is connected to the nut 3 to be tightened or loosened. By rotating the mounting part 1, the nut 3 connected to the pre-tightening part 2 rotates, thereby tightening or loosening the nut 3.

[0040] The pre-tightening fixture can be connected to the nut 3 by having the inner wall of the pre-tightening part 2 abut against the outer circumferential surface of the nut 3, or by having the end of the connector 21 away from the locking part 22 embedded in the nut 3, so that the connector 21 and the nut 3 form a limiting fit, thereby enabling the pre-tightening part 2 and the nut 3 to be detachably connected.

[0041] The end part is connected by the locking piece 22 and the connecting piece 21, so that the connecting piece 21 is fixed to the specified position of the mounting part 1, thereby fixing the diameter size of the pre-tightening part 2 according to the set size, and further improving the stability when the pre-tightening tool is connected with the nut 3 to be tightened, effectively improving the connection strength of the pre-tightening tool and the nut 3, and improving the stability when the nut 3 is tightened or loosened.

[0042] In the embodiment of the present application, the distance between the pre-tightening part 2 and the center of the mounting part 1 is adjustable, so that the diameter size of the pre-tightening part 2 can be adjusted, thereby adapting to nuts 3 of different sizes to be tightened or loosened, effectively improving the adaptability of the pre-tightening tool, and the connecting piece 21 of the pre-tightening part 2 is detachably connected with the locking piece 22 and the mounting part 1, which not only facilitates the adjustment of the diameter size of the pre-tightening part 2 to adapt to nuts 3 of different sizes, but also facilitates the replacement of parts of the pre-tightening tool, thereby reducing the labor intensity of manually tightening or loosening the nut 3 and improving the work efficiency.

[0043] In one example, the connecting piece 21 has a first end 211 and a second end 212 arranged oppositely, the first end 211 is detachably connected with the locking piece 22, and the second end 212 has a protruding part 213 connected with the nut 3.

[0044] As shown in Figures 1 to 4 The first end 211 of the connecting piece 21 is the top end of the connecting piece 21, and the second end 212 of the connecting piece 21 is the bottom end of the connecting piece 21. The connecting piece 21 is prismatic, and the top end of the connecting piece 21 is cylindrical. The top end of the connecting piece 21 has external threads, and the end part is connected with the locking piece 22 through the mounting part 1. The locking piece 22 is a locking nut 3. By connecting the locking nut 3 with the cylindrical top end of the connecting piece 21, the connecting piece 21 can be fixed to the specified position of the mounting part 1, thereby limiting the diameter size of the pre-tightening part 2 of the pre-tightening tool to adapt to the nut 3 to be tightened or loosened.

[0045] The connecting piece 21 is detachably connected with the mounting part 1 through the locking nut 3, which not only facilitates the adjustment of the diameter size of the pre-tightening part 2 of the pre-tightening tool, but also facilitates the disassembly of the pre-tightening tool for replacement of damaged parts, thereby effectively reducing the maintenance and / or use cost of the pre-tightening tool.

[0046] The second end 212 of the connecting piece 21 has a protruding part 213. The protruding part 213 is connected with the nut 3 to be tightened or loosened. The protruding part 213 can be in contact with the outer circumferential surface of the nut 3 to be tightened or loosened through the side close to the axis of the mounting part 1, or the protruding part 213 can be embedded in the nut 3 to be tightened or loosened, so that the connecting piece 21 is connected with the nut 3 to be tightened or loosened, and further rotates the nut 3 to be tightened or loosened by rotating the pre-tightening tool.

[0047] In one example, one side of the protruding part 213 is connected with the second end 212, and the diameter of the protruding part 213 gradually decreases from the side of the connecting part 21 towards the protruding part 213.

[0048] As shown in Figures 1 to 4 The protruding part 213 is wedge-shaped, and the longitudinal section of the protruding part 213 is a right trapezoid. The top end of the protruding part 213 is connected with the second end 212 of the connecting part 21. The longitudinal section of the protruding part 213 gradually decreases from the top end to the bottom end. The side of the protruding part 213 close to the axis direction of the mounting part 1 is a vertical surface, which is in contact with the outer circumferential surface of the nut 3 to be tightened or loosened when the pretightening tool is connected with the nut 3 to be tightened or loosened.

[0049] Of course, the protruding part 213 is not limited to the above structure in the embodiment of the present application, and those skilled in the art can set it according to actual needs. For example, the side of the protruding part 213 close to the axis direction of the mounting part 1 is an arc surface, and the curvature of the arc surface is the same as the curvature of the outer circumferential surface of the nut 3 to be tightened or loosened.

[0050] The protruding part 213 is set as a wedge-shaped structure to avoid the peripheral parts of the nut 3 to be tightened or loosened, so that the protruding part 213 can be embedded in the outer circumferential edge of the nut 3 to be tightened or loosened, and the protruding part 213 can be connected with the nut 3 to be tightened or loosened.

[0051] In one example, the mounting part 1 has an adjusting hole 11, the adjusting hole 11 is arranged along the radial direction of the mounting part 1, and one end of the connecting part 21 passes through the adjusting hole 11 and is detachably connected with the locking part 22.

[0052] As shown in Figures 1 to 4 The mounting part 1 is a circular plate, and the adjusting hole 11 is a waist-shaped hole. The waist-shaped hole is arranged along the radial direction of the mounting part 1.

[0053] A plurality of waist-shaped holes are equiangularly distributed on the mounting part 1, and the plurality of waist-shaped holes are arranged along the circumferential direction of the mounting part 1. As shown in Figures 1 to 4 Three waist-shaped holes are equiangularly distributed on the mounting part 1.

[0054] The top end of the connecting part 21, i.e. the cylindrical end, passes through the waist-shaped hole and is connected with the locking part 22. When the locking part 22 is loosened, the top end of the connecting part 21 can move along the waist-shaped hole, i.e. the connecting part 21 moves along the radial direction of the mounting part 1, and the diameter of the pretightening part 2 is adjusted. After being adjusted to the required position, the locking part 22 is tightened to fix the connecting part 21 at the position of the waist-shaped hole, so as to lock the diameter of the pretightening part 2 to adapt to the diameter of the nut 3 to be tightened or loosened.

[0055] In this embodiment of the application, the connecting part 21 of the pre-tightening fixture can be adjusted along the radial direction of the mounting part 1 to meet the pre-tightening operation of the round nuts 3 of M100 to M180.

[0056] The locking member 22 is detachably connected to the first end 211 of the connector 21, which not only facilitates the adjustment of the diameter of the pre-tightening part 2 of the pre-tightening fixture, but also facilitates the disassembly of the locking member 22 and the connector 21, so that the connector 21 is disengaged from the adjustment hole 11, thereby separating the pre-tightening part 2 from the mounting part 1, so that damaged parts can be replaced individually, effectively reducing the maintenance and / or use cost of the pre-tightening fixture.

[0057] In one example, a reinforcing member is fitted onto the connector 21, the reinforcing member being located between the locking member 22 and the mounting part 1.

[0058] like Figures 1 to 4 As shown, a reinforcing member is fitted onto the first end 211 of the connector 21, that is, a reinforcing member is fitted onto the cylindrical end of the connector 21. The diameter of this reinforcing member is larger than the circumferential dimension of the adjusting hole 11 in the mounting part 1, and the diameter of this reinforcing member is larger than the diameter of the locking member 22. When the connector 21 is connected to the mounting part 1, by providing this reinforcing member between the locking member 22 and the mounting part 1, the contact force and friction between the locking member 22 and the mounting part 1 can be effectively enhanced, thereby improving the connection strength between the connector 21 and the mounting part 1.

[0059] In one example, the reinforcement includes a flat washer 214, which is sleeved on one end of the connector 21 that extends out of the adjustment hole 11, and the flat washer 214 is located between the locking member 22 and the adjustment hole 11.

[0060] like Figures 1 to 4 As shown, the reinforcing component includes an annular flat washer 214. The flat washer 214 is sleeved on the first end 211 of the connector 21 and is located between the locking member 22 and the mounting part 1. The diameter of the flat washer 214 is larger than the circumferential dimension of the adjusting hole 11 in the mounting part 1, and the diameter of the flat washer 214 is larger than the diameter of the locking member 22. This increases the friction between the locking member 22 and the mounting part 1 through the flat washer 214 when the locking member 22 and the connector 21 are tightened, thereby improving the stability of the locking member 22 at the position of the adjusting hole 11. This prevents the connector 21 from moving along the adjusting hole 11 during the use of the pre-tightening fixture, which would cause a change in the diameter of the pre-tightening part 2, and consequently worsen the connection stability between the pre-tightening fixture and the nut 3 to be tightened or loosened.

[0061] In one example, the reinforcement includes a spring pad 215, which is sleeved on one end of the connector 21 that passes through the adjustment hole 11. The spring pad 215 is located between the mounting part 1 and the locking member 22, and the spring pad 215 is capable of elastic deformation along the axial direction of the connector 21.

[0062] like Figures 1 to 4 As shown, a spring washer 215 is fitted onto the first end 211 of the connector 21, which is located between the locking member 22 and the mounting part 1. The diameter of the spring washer 215 is larger than the circumferential dimension of the adjusting hole 11 in the mounting part 1, and the diameter of the flat washer 214 is larger than the diameter of the locking member 22. The spring washer 215 has tension and can elastically deform along the axial direction of the connector 21. When the locking member 22 and the connector 21 are tightened, the spring washer 215 is compressed by the locking member 22, and the spring washer 215 forms tension in the direction of the locking member 22 and the mounting part 1 to enhance the connection between the locking member 22 and the mounting part 1, thereby improving the stability of the locking member 22 at the position of the adjusting hole 11 and preventing the locking member 22 from loosening during the use of the pre-tightening fixture, which would lead to a decrease in the connection stability between the pre-tightening fixture and the nut 3 to be tightened or loosened.

[0063] Of course, the elastic pad 215 in this embodiment is not limited to the structure described above, and those skilled in the art can configure it according to actual needs. For example, the elastic pad 215 can be an elastic gasket or an elastic element such as a spring.

[0064] In one example, the mounting part 1 is provided with a knob 12, which is located at the axis of the mounting part 1.

[0065] like Figures 1 to 4 As shown, the mounting part 1 is in the shape of a circular plate, and a knob 12 is provided at the center of the mounting part 1. The knob 12 and the locking member 22 are on the same side of the mounting part 1. When the pre-tightening fixture is connected to the nut 3 to be tightened or loosened, the knob 12 is connected to the device such as a pneumatic wrench so that the pre-tightening fixture can be rotated by the knob 12, thereby driving the nut 3 to be tightened or loosened to rotate.

[0066] In one example, the mounting part 1 is provided with scale lines located at the edge of the adjustment hole 11.

[0067] like Figures 1 to 4 As shown, a scale line is provided at the edge of the adjustment hole 11. The scale line improves the accuracy of the adjustment connector 21 in the position of the adjustment hole 11, thereby improving the accuracy of the diameter of the pre-tightening part 2. The diameter of the pre-tightening part 2 can be adjusted by adjusting the adjustment hole 11.

[0068] According to another embodiment of the present application, a screwing device is provided, which comprises a nut 3 and the pre-tightening tool as described above.

[0069] As shown in Figures 1 to 4 the nut 3 is a circular nut 3. Of course, the nut 3 is not limited to the above structure in the embodiments of the present application, and a person skilled in the art can set it according to actual needs. For example, the external shape of the nut 3 is polygonal.

[0070] In the embodiments of the present application, the nut 3, the flat washer 214 and the elastic washer 215 to be screwed or loosened are standard parts, the installation part 1 and the pre-tightening part 2 have small machining sizes and low machining requirements, which can effectively reduce the manufacturing cost.

[0071] The pre-tightening tool has large strength, high hardness and long service life, and has simple structure, easy manufacturing, easy processing and assembly, and effectively reduces the production cost.

[0072] The pre-tightening tool is simple and convenient to operate, which is beneficial to the production standardization, can reduce the labor intensity and improve the assembly efficiency.

[0073] In one example, the nut 3 has a plurality of limiting grooves 31 uniformly distributed on the outer circumferential surface of the nut 3, and in the connected state of the nut 3 and the pre-tightening tool, the limiting grooves 31 and the connecting piece 21 form a limiting fit in the radial direction, and the second end 212 of the connecting piece 21 and the nut 3 form a limiting fit in the axial direction.

[0074] As shown in Figures 1 to 4 the nut 3 is a circular nut 3. The outer circumferential surface of the nut 3 is provided with a plurality of limiting grooves 31 at equal angles. The limiting grooves 31 are matched with the protruding part 213 of the connecting piece 21. In the connected state of the pre-tightening tool and the nut 3, the protruding part 213 of the connecting piece 21 is embedded in the limiting groove 31. By embedding the protruding part 213 in the limiting groove 31, the rotation angle of the nut 3 in the circumferential direction is limited, and by rotating the limiting tool, the protruding part 213 drives the nut 3 to rotate, and then the nut 3 is screwed or loosened.

[0075] The dimension of the protrusion 213 along the circumferential direction of the mounting portion 1 is smaller than the dimension of the second end 212 of the connector 21 along the axial direction of the mounting portion 1. That is, the opposite ends of the connector 21 protrude from the protrusion 213. When the pre-tightening fixture is connected to the nut 3, the protrusion 213 is embedded in the limiting groove 31, and the opposite ends of the second end 212 of the connector 21 abut against the top of the nut 3 to be tightened or loosened along the axial direction of the mounting portion 1. By abutting the top of the nut 3 to be tightened or loosened, the position of the two in the axial direction is limited, and the protrusion 213 is prevented from being embedded too deeply in the axial direction of the nut 3 to be tightened or loosened, thus preventing damage to other components.

[0076] How to use the pre-tightening fixture with the nut 3 to be tightened or loosened:

[0077] like Figure 4 Figure 4 Figures 1 to 4 As shown, three adjusting holes 11 are evenly distributed radially on the mounting part 1. The prism part of the connector 21 is clearance-fitted with the adjusting holes 11 in the mounting part 1, allowing the connector 21 to translate radially along the circular mounting part 1. The prism part of the connector 21 acts as a limit to prevent the connector 21 from rotating axially. The adjusting holes 11 have scale lines along their edges to ensure that the three connectors 21 are at the same distance from the center of the circular mounting part 1. When the locking part 22 is tightened onto the connector 21, the connector 21 no longer moves and becomes an integral part of the mounting part 1.

[0078] The pre-tightening fixture for nuts 3 to be tightened or loosened is used in the pre-tightening process of round nuts 3 at the yaw and pitch reducer assembly site. By adjusting the distance of the tightening connector 21 in the radial direction of the mounting part 1, it can accommodate various specifications of nuts 3 to be tightened or loosened. The pre-tightening fixture is assembled into the limiting groove 31 of the nut 3 to be tightened or loosened, and the pre-tightening fixture is driven by an electric wrench or pneumatic wrench to perform the pre-tightening work on the nut 3 to be tightened or loosened. This can effectively reduce the use of manual labor and improve on-site assembly efficiency.

[0079] While specific embodiments of this application have been described in detail by way of examples, those skilled in the art should understand that the above examples are for illustrative purposes only and are not intended to limit the scope of this application. Those skilled in the art should understand that modifications can be made to the above embodiments without departing from the scope and spirit of this application. The scope of this application is defined by the appended claims.

Claims

1. A pre-tensioning tool applied to a nut (3), characterized in that, The pre-tightening device comprises a mounting part (1) and a plurality of pre-tightening parts (2), the pre-tightening parts (2) are arranged in a circular array on the mounting part (1) with the center of the mounting part (1) as the array center, and the distance between the pre-tightening parts (2) and the center of the mounting part (1) is adjustable. The pre-tightening part (2) comprises a connecting piece (21) and a locking piece (22), the opposite ends of the connecting piece (21) are detachably connected with the nut (3) and the mounting part (1) respectively, and one end of the connecting piece (21) connected with the nut (3) protrudes out of the mounting part (1).

2. The preloading tooling of claim 1, wherein, The connecting piece (21) has oppositely arranged first and second ends (211 and 212), the first end (211) is detachably connected with the locking piece (22), and the second end (212) has a protruding part (213) connected with the nut (3).

3. The preloading tooling of claim 2, wherein, One side of the protruding part (213) is connected with the second end (212), and the diameter of the protruding part (213) gradually decreases from one side of the connecting piece (21) towards the protruding part (213).

4. The preloading tooling of claim 1, wherein, The mounting part (1) has an adjusting hole (11) arranged thereon, the adjusting hole (11) is arranged along the radial direction of the mounting part (1), one end of the connecting piece (21) passes through the adjusting hole (11) and is detachably connected with the locking piece (22).

5. The preloading tooling of claim 4, wherein, A reinforcing piece is arranged on the connecting piece (21) and located between the locking piece (22) and the mounting part (1).

6. The preloading tooling of claim 5, wherein, The reinforcing piece comprises a flat pad (214) arranged on the connecting piece (21), and the flat pad (214) is located between the locking piece (22) and the adjusting hole (11).

7. The preloading tool of claim 5, wherein The reinforcing piece comprises an elastic pad (215) arranged on one end of the connecting piece (21) passing through the adjusting hole (11), and the elastic pad (215) is located between the mounting part (1) and the locking piece (22), and the elastic pad (215) can be elastically deformed along the axial direction of the connecting piece (21).

8. The preloading tool of claim 6, wherein, A knob (12) is arranged on the mounting part (1) and located at the center of the mounting part (1).

9. A screwing device, characterized in that The pre-tightening device comprises a nut (3) and the pre-tightening device as claimed in any one of claims 1-8.

10. A screwing device according to claim 9, characterized in that The nut (3) has a limiting groove (31) arranged on the outer circumferential surface of the nut (3), and the limiting groove (31) forms a limiting fit with the connecting piece (21) along the radial direction when the nut (3) is connected with the pre-tightening device, and the second end (212) of the connecting piece (21) forms a limiting fit with the nut (3) along the axial direction.

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