Nut assembling mechanism and bolt and nut assembling device

Abstract

The invention belongs to the technical field of machinery for tightening or loosening screws or nuts, and particularly provides a nut assembling mechanism and a bolt and nut assembling device. The nut assembling mechanism comprises a support, a nut anti-rotation piece is fixed to the support and provided with a nut groove, an ejector rod is movably assembled on the support and provided with an elastic piece enabling the ejector rod to automatically return to the position, a penetrating hole allowing the ejector rod to penetrate out is formed in the center of the nut groove, and the peripheral size of the ejector rod is smaller than the inner diameter of a nut. The ejector rod protrudes out of a groove opening of the nut groove, the protruding part can be inserted into a bolt hole of an assembled flange, and the elastic deformation stroke of the elastic piece which is compressed or stretched meets the requirement that the ejector rod retreats from the nut groove. The bolt and nut assembling device comprises the nut assembling mechanism. When the bolt is screwed, along with jacking of the bolt, after the ejector rod is stressed, the elastic piece elastically deforms and retreats, the bolt smoothly penetrates through the gasket to be connected with the nut, one-time assembling operation is completed, and the assembling success rate is increased.

Description

Technical Field

[0001] The invention belongs to the technical field of machinery for tightening or loosening screws or nuts, and in particular relates to a nut assembly mechanism and a bolt and nut assembly device. Background Art

[0002] During the assembly and manufacturing process of high-voltage switchgear, flange bolt connection structures are widely used to connect different components. Currently, operations such as threading bolts and tightening nuts are still performed manually, with a low degree of automation and high labor intensity.

[0003] With the continuous development of intelligent manufacturing, technologies such as machine vision technology, working manipulators, human-computer interaction technology, and intelligent sensing technology have also made rapid progress. Existing technologies have also begun to appear in automated intelligent assembly technologies for bolt and nut structures. For example, in the automotive manufacturing, wind power and other industries, multi-degree-of-freedom manipulators have been widely used in conjunction with machine vision systems to automatically complete the assembly of bolts and nuts. However, in the above industries, most of them are to screw bolts into threaded holes and nuts into bolts (screws), etc., and generally do not involve the matching connection of bolts and nuts for flange through-hole (light hole) structures.

[0004] The patent document with application publication number CN113843782A discloses a column flange bolt tightening robot that can intelligently identify steel structure assembly deviations. The robot includes a bolt joint system (i.e., a bolt assembly mechanism), a nut joint system (i.e., a nut assembly mechanism), a robot arm, a visual perception module, a sensor, etc. The bolt joint system includes a bolt tightening head (i.e., a tightening head) for tightening the bolt. The nut joint system includes a nut groove, in which a compression spring is provided. The nut can be placed in the nut groove and pushed toward the flange under the action of the compression spring. In addition, the nut joint system also includes a nut pre-positioning plate, which can be magnetically adsorbed on the flange, and the nut pre-positioning plate is provided with a groove that cooperates with the nut to stop the rotation, providing a large reaction force for screwing in the bolt. The bolt tightening head of the bolt joint system can grab one end of the bolt head of the bolt and drive the bolt to rotate. The robot can automatically complete the assembly of bolts and nuts through the bolt joint system, the nut joint system, the robot arm, and the visual perception module.

[0005] However, when assembling high-voltage switchgear, in order to improve the reliability of the bolt and nut connection, a gasket is often required between the nut and the flange. In the above-mentioned nut joint system, the structure that carries the nut to the specified position and prevents the nut from rotating is the nut groove. The gasket is thin and light. If the nut and gasket are all placed in the nut groove, the gasket is easy to fall out of the nut groove during the movement into place, resulting in assembly failure and a low success rate. Summary of the invention

[0006] The purpose of the present invention is to provide a nut assembly mechanism to solve the technical problem that the nut assembly mechanism in the prior art has a low success rate when assembling nuts and washers. The purpose of the present invention is also to provide a bolt and nut assembly device to solve the same technical problem.

[0007] To achieve the above object, the technical solution of the nut assembly mechanism provided by the present invention is: A nut assembly mechanism includes a support, a nut anti-rotation part is fixed on the support, the nut anti-rotation part has a nut groove for the assembled nut to enter and cooperate with the nut to stop rotation, a push rod is movably assembled on the support, the push rod is equipped with an elastic part that automatically returns to its position, a through hole is provided at the center of the nut groove for the push rod to pass through, and the outer circumference of the push rod is smaller than the inner diameter of the nut, when the elastic part is in a natural state, the push rod protrudes from the notch of the nut groove, and the protruding part can be inserted into the bolt hole of the assembled flange, and the elastic deformation stroke of the elastic part being compressed or stretched satisfies the withdrawal of the push rod from the nut groove.

[0008] As a further improvement, a fixed sleeve is installed on the support, the nut anti-rotation member is installed on the fixed sleeve, the elastic member is arranged inside the fixed sleeve, and one end of the push rod is located inside the fixed sleeve.

[0009] As a further improvement, the two ends of the fixed sleeve have different calibers, and it has a large diameter end and a small diameter end. The part of the push rod located inside the fixed sleeve is provided with a stop structure, and the stop structure cooperates with the small diameter end stop.

[0010] As a further improvement, the elastic member is a compression spring, one end of the compression spring abuts against the support, and the other end abuts against the stop structure, and a portion of the push rod penetrates into the compression spring.

[0011] The present invention is a pioneering invention, and its beneficial effects are as follows: during implementation, the nut assembly mechanism can be installed on a multi-degree-of-freedom mechanical arm through a support, and when picking up the nut and the gasket, the nut can enter the nut groove of the nut anti-rotation part, and under the action of the elastic part, the push rod can be inserted into the nut and the gasket, forming a "series" structure. When the elastic part is in a natural state, the protruding part of the push rod can be inserted into the bolt hole of the flange. At this time, the push rod is equivalent to a support beam supporting the nut and the gasket, which can ensure that the nut and the gasket do not fall off, and the push rod also has a certain positioning and guiding effect. When the bolt is screwed in, as the bolt is pushed in, the push rod is subjected to force, causing the elastic part to elastically deform and retreat, and the bolt smoothly passes through the gasket and connects with the nut, completing an assembly operation, thereby improving the assembly success rate.

[0012] To achieve the above-mentioned purpose, the technical solution of the bolt and nut assembly device provided by the present invention is: A bolt and nut assembly device comprises a bolt assembly mechanism and a nut assembly mechanism, the bolt assembly mechanism comprises a bracket, a rotatable tightening head and a driving device for driving the tightening head to rotate are installed on the bracket, the tightening head is provided with a bolt tightening mechanism for picking up the assembled bolt and cooperating with the bolt to stop rotation, the nut assembly mechanism comprises a support, a nut anti-rotation part is fixed on the support, the nut anti-rotation part has a nut groove for the assembled nut to enter and cooperates with the nut to stop rotation, a push rod is movably assembled on the support, the push rod is provided with an elastic part for automatically returning to its position, a through hole for the push rod to pass through is provided at the center of the nut groove, and the outer circumferential size of the push rod is smaller than the inner diameter of the nut, when the elastic part is in a natural state, the push rod protrudes from the notch of the nut groove, and the protruding part can be inserted into the bolt hole of the assembled flange, and the elastic deformation stroke of the elastic part being compressed or stretched satisfies the withdrawal of the push rod from the nut groove.

[0013] As a further improvement, a fixed sleeve is installed on the support, the nut anti-rotation member is installed on the fixed sleeve, the elastic member is arranged inside the fixed sleeve, and one end of the push rod is located inside the fixed sleeve.

[0014] As a further improvement, the two ends of the fixed sleeve have different calibers, and it has a large diameter end and a small diameter end. The part of the push rod located inside the fixed sleeve is provided with a stop structure, and the stop structure cooperates with the small diameter end stop.

[0015] As a further improvement, the elastic member is a compression spring, one end of the compression spring abuts against the support, and the other end abuts against the stop structure, and a portion of the push rod penetrates into the compression spring.

[0016] As a further improvement, an auxiliary support structure is installed on the bracket, the auxiliary support structure includes a moving seat that can move relative to the bracket and a driving device for driving the moving seat to move, a support rod is installed on the moving seat, and the support rod is provided with a support structure for supporting the bolt, and the moving stroke of the moving seat satisfies the support rod to move to a position where the support structure contacts the bolt support and a position where the support rod is completely separated from the bolt and avoids the bolt head.

[0017] As a further improvement, the support rod is movably assembled on the moving seat, and an elastic body is connected between the support rod and the moving seat.

[0018] As a further improvement, a guide member is installed on the bracket and is located at the tightening head and extends in a direction perpendicular to the rotation axis of the tightening head, and the movable seat is guided and installed on the guide member.

[0019] As a further improvement, the support structure has a V-shaped support surface.

[0020] As a further improvement, the driving device for driving the tightening head to rotate is a motor equipped with a torque sensor.

[0021] The present invention belongs to an improved invention creation, and its beneficial effects are: during implementation, the nut assembly mechanism can be installed on a multi-degree-of-freedom mechanical arm through a support, and when picking up the nut and the gasket, the nut can enter the nut groove of the nut anti-rotation part, and under the action of the elastic part, the push rod can be inserted into the nut and the gasket, forming a "series" structure. When the elastic part is in a natural state, the protruding part of the push rod can be inserted into the bolt hole of the flange. At this time, the push rod is equivalent to a support beam supporting the nut and the gasket, which can ensure that the nut and the gasket do not fall off, and the push rod also has a certain positioning and guiding effect. When the bolt is screwed in, as the bolt is pushed in, the push rod is subjected to force to cause the elastic part to elastically deform and retreat, and the bolt smoothly passes through the gasket and connects with the nut, completing an assembly operation, thereby improving the assembly success rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a structural schematic diagram of an embodiment of a bolt and nut assembly device in the present invention; Figure 2 A cross-sectional view of an embodiment of a bolt and nut assembly device of the present invention; Figure 3 for Figure 1 Schematic diagram of the end of the middle nut anti-rotation part; Figure 4 for Figure 1 Schematic diagram of the end of the tightening head.

[0023] Description of reference numerals: 1. Support; 2. First sleeve; 3. Camera; 4. Tightening head; 5. Bracket; 6. Driving motor; 7. Guide rail; 8. Moving seat; 9. Second sleeve; 10. Support rod; 11. Support structure; 12. Nut anti-rotation member; 13. Push rod; 14. Stop structure; 15. First compression spring; 16. Second compression spring; 100. Flange; 200. Bolt hole; 300. Assembled bolt; 400. Assembled nut; 500. Assembled gasket. DETAILED DESCRIPTION

[0024] In order to improve the success rate of nut and bolt installation, the basic technical concept of the present invention is to set a movable push rod on the nut assembly mechanism for installing the nut. When picking up the nut and the gasket, the push rod penetrates the inner hole of the nut and the gasket to "series" the nut and the gasket. When assembling the nut, a part of the push rod can be inserted into the bolt hole of the flange. During the assembly process, as the bolt is pushed in, the push rod retreats to meet the normal connection between the bolt and the nut. The present invention is further described in detail below in conjunction with the embodiments.

[0025] Specific embodiments of the bolt and nut assembly device provided by the present invention: The bolt and nut assembly device provided in this embodiment is as follows: Figure 1 and Figure 2As shown, it includes a bolt assembly mechanism and a nut assembly mechanism. The bolt assembly mechanism is used to pick up and drive the bolt to rotate, and the nut assembly mechanism is used to pick up the nut and prevent the nut from rotating during the process of screwing the bolt. Both the bolt assembly mechanism and the nut assembly mechanism can be installed at the end of the multi-degree-of-freedom robot arm, and serve as the actuator at the end to complete the normal assembly of the bolt and nut. The multi-degree-of-freedom robot arm is a prior art and will not be expanded here. The following is a detailed description mainly focusing on the differences between the present invention and the prior art.

[0026] Nut assembly mechanism ( Figure 1-Figure 2 The left part) includes a support 1, which can be fixedly mounted on the multi-degree-of-freedom robot arm through the support 1, and can move (translation, rotation, etc.) under the action of the multi-degree-of-freedom robot arm. A nut anti-rotation member 12 is fixedly mounted on the support 1. The nut anti-rotation member 12 has a nut groove for the assembled nut 400 to enter and cooperate with the nut to stop rotation. Specifically, as shown in FIG. Figure 3 As shown, the nut slot is an internal hexagonal structure with a certain depth, preferably to allow the nut to fully enter, so as to have the best anti-rotation and anti-falling effect. Of course, in order to prevent the nut from falling off, a magnetic adsorption member can also be provided on the nut anti-rotation member 12 to adsorb the assembled nut 400.

[0027] The support 1 is equipped with a push rod 13, and the push rod 13 and the support 1 are movably matched. In other words, the push rod 13 is movably assembled on the support 1. An elastic member is connected between the push rod 13 and the support 1. The elastic force generated by the elastic member being compressed or stretched can act on the push rod 13, so that the push rod 13 automatically returns to a certain position. A through hole is provided at the center of the nut groove for the push rod 13 to pass through, so that there is a basis for the push rod 13 to pass out. In a preferred case, the through hole and the guide of the push rod 13 are matched, so that the stability of the movement of the push rod 13 can be ensured. The outer circumference of the push rod 13 is smaller than the inner diameter of the assembled nut 400, so that there is a situation that the push rod 13 is inserted into the assembled nut 400. It should be noted that the push rod 13 in this embodiment can be a round rod, and the outer circumference of the push rod 13 refers to the outer diameter of the push rod 13. However, the push rod 13 in other embodiments can also be a rod with a polygonal cross-section, and the outer circumference of the push rod 13 refers to the outer contour of the push rod 13.

[0028] When the elastic member is in a natural state, Figure 2 As shown, the push rod 13 protrudes from the notch of the nut groove on the nut anti-rotation member 12. Specifically, the elastic member can be a compression spring, and for the convenience of accurate understanding, the compression spring here is defined as the first compression spring 15.

[0029] Considering that when nuts and bolts are installed to connect the flange 100 (only part of the figure is shown), in order to improve the stability of the connection, a gasket may be added between the nut and the flange 100. Of course, the push rod 13 can also penetrate the assembled gasket 500 on the basis of satisfying the requirement of penetrating the assembled nut 400. Specifically, the gasket can be a flat gasket, a spring gasket, etc., or a combination of a flat gasket and a spring gasket. In this way, when assembling the nut, the push rod 13 can penetrate the assembled nut 400 and the assembled gasket 500 at the same time, and the assembled nut 400 and the assembled gasket 500 are "series" connected together, which can prevent the nut and the gasket from falling off. Of course, the inner size and depth of the nut groove can also be flexibly set according to the size and thickness of the gasket, so that the assembled gasket 500 can also enter the nut groove.

[0030] like Figure 1 and Figure 2 As shown, the bolt assembly mechanism includes a bracket 5, which can be installed on a multi-degree-of-freedom robot arm through the bracket 5, and can move (translate, rotate, etc.) under the action of the multi-degree-of-freedom robot arm. A rotatable tightening head 4 and a driving device for driving the tightening head 4 to rotate are installed on the bracket 5. The driving device can be an electric drive device, that is, a driving motor 6. However, in other embodiments, the use of air drive or liquid drive is not excluded. The tightening head 4 is equipped with a bolt tightening mechanism for picking up the assembled bolt 300 and cooperating with the assembled bolt 300 to stop rotation. Specifically, as Figure 4 As shown, for the external hexagonal bolt, the bolt tightening mechanism can be in the form of an internal hexagonal groove for the bolt head of the external hexagonal bolt to enter. Of course, for the internal hexagonal bolt, the bolt tightening mechanism can be a hexagonal columnar structure inserted into the bolt head of the internal hexagonal bolt.

[0031] When assembling bolts and nuts, for the bolt assembly mechanism, after the bracket 5 picks up the assembled bolt 300, it can drive the bolt to move toward the bolt hole 200 of the flange 100. After aligning with the bolt hole 200, the bracket 5 continues to move, the assembled bolt 300 enters the bolt hole 200, and the drive motor 6 is started to drive the assembled bolt 300 to rotate. For the nut assembly mechanism, after the nut anti-rotation member 12 and the push rod 13 pick up the assembled nut 400 and the assembled gasket 500, the support 1 drives the nut and the gasket to move toward the bolt hole 200 of the flange 100. After aligning with the bolt hole 200, the support 1 continues to move, so that the assembled gasket 500 is pressed on the bolt hole 200 of the flange 100. At this time, the protruding part of the push rod 13 can be inserted into the bolt hole 200. In this state, the assembled gasket 500 and the assembled nut 400 are reliably strung on the push rod 13 and will not fall off. As the assembled bolt 300 is screwed in, when the bolt hits the push rod 13, the push rod 13 will retreat after being stressed. When the elastic member is the first compression spring 15, the elastic member is compressed. At this time, the elastic deformation stroke of the elastic member is required to satisfy the withdrawal of the push rod 13 from the nut groove. This can ensure that the assembled bolt 300 and the assembled nut 400 are screwed together normally, and the elastic force of the elastic member pushes the push rod 13 to automatically return to the position where a part of the push rod 13 protrudes out of the nut groove.

[0032] As a preferred embodiment, Figure 1 and Figure 2 As shown, a fixed sleeve is installed on the support 1. For ease of understanding, the fixed sleeve is defined as the first sleeve 2. The elastic member is arranged inside the first sleeve 2, and one end of the push rod 13 is located inside the first sleeve 2. At this time, the first sleeve 2 can limit the compression or stretching direction of the elastic member, ensuring that the push rod 13 can operate stably.

[0033] Based on the above embodiments, as a more preferred embodiment, Figure 1 and Figure 2 As shown, the calibers of the two ends of the first sleeve 2 are different, and it has a large diameter end and a small diameter end. The left end in the figure is the large diameter end, and the right end is the small diameter end. The part of the push rod 13 located inside the first sleeve 2 is provided with a stop structure 14, and the stop structure 14 cooperates with the small diameter end to prevent the push rod 13 from coming out of the first sleeve 2. This is equivalent to adding a safety measure. The stop structure 14 cooperates with the small diameter end to limit the extreme position of the push rod 13, thereby preventing the elastic member from being over-tensioned and deformed. Specifically, the stop structure 14 can be an annular step as shown in the figure, or a boss arranged at intervals in the circumferential direction. The stop structure 14 can also contact the inner wall of the first sleeve 2 to form a guiding cooperation relationship, thereby making the movement of the push rod 13 more stable.

[0034] Furthermore, one end of the first compression spring 15 abuts against the support 1, and the other end abuts against the stop structure 14, and the push rod 13 partially penetrates into the first compression spring 15. In this way, it is not necessary to use a fastening structure such as a welding structure to fasten the two ends of the first compression spring 15 to the support 1 and the elastic member, respectively, which is convenient and efficient. At the same time, the push rod 13 penetrates into the first compression spring 15 and also has the function of guiding the first compression spring 15 to be compressed.

[0035] It should be noted here that, in addition to the preferred embodiments described above, there may be many other ways to install the elastic member. For example, the elastic member may be a tension spring, an elastic pull rope, etc. that is stretched and deformed. One end of the elastic member may be connected to the top rod 13 through a fastening connection structure, and the other end may be connected to a connecting member (such as the first sleeve 2) provided on the support 1 through a fastening connection structure. The connecting member that connects the nut anti-rotation member 12 and the support 1 may not be the first sleeve 2. It may be a C-shaped structure that is not completely closed in the circumferential direction of the cross section, or a frame structure formed by splicing multiple rods. A person skilled in the art is aware that it is impossible to enumerate all possible forms. According to the actual structure of the support 1, a person skilled in the art has a reasonable form of deformable elastic member, installation position, etc., so that the elastic deformation force of the elastic member drives the top rod 13 to automatically return to its position.

[0036] Regarding the bolt assembly mechanism, considering that in some cases, the length of the assembled bolt 300 is relatively long, only the tightening head 4 drives the assembled bolt 300 to move, which will form a cantilever beam structure with a relatively long moment and insufficient stability. To solve this problem, in a preferred embodiment, as Figure 1 and 2 As shown, the bracket 5 is also equipped with an auxiliary support structure 11, which includes a moving seat 8 that can move relative to the bracket 5 and a driving device (not shown in the figure) that drives the moving seat 8 to move. A support rod 10 is installed on the moving seat 8, and a support structure 11 for supporting bolts is provided on the support rod 10. The moving stroke of the moving seat 8 satisfies the position where the support rod 10 moves to the position where the support structure 11 contacts the bolt support and the position where the bolt head is completely separated from the bolt and avoided. By adding the auxiliary support structure 11, the support of the bolt assembly mechanism for the assembled bolt 300 can be changed from a cantilever beam structure to a simply supported beam structure, making the assembled bolt 300 more stable.

[0037] In a more preferred embodiment, the support rod 10 is movably mounted on the movable seat 8, and an elastic body is connected between the support rod 10 and the movable seat 8. In this way, during the process of screwing the bolts, when the support structure 11 is against the flange 100, the support rod 10 can be retreated as the bracket 5 moves, ensuring that the auxiliary support structure 11 can also play a certain role in the process of screwing the bolts. After the installation is completed, the elastic force of the elastic body pushes the support rod 10 to automatically reset. The elastic body here can also be a compression spring, that is, the second compression spring 16 shown in the figure. Of course, the second compression spring 16 and the support rod 10 can also be set in a manner similar to the push rod 13 and the first compression spring 15 system. For example, a fixed sleeve (second sleeve 9) can be configured to set the second compression spring 16 in the second sleeve 9.

[0038] Since the movable base 8 needs to move to drive the supporting structure 11 to avoid the assembled bolts 300, in a preferred embodiment, the movement here can be a linear motion with a certain direction, such as Figure 1 and Figure 2 As shown, a guide extending in a direction perpendicular to the rotation axis of the tightening head 4 (radial direction) is installed on the bracket 5, and the movable seat 8 is guided and installed on the guide. This makes it easier to determine the position of the support structure 11 and to control the movement of the movable seat 8. Specifically, the guide can be a guide rail 7, and the movable seat 8 is provided with a slider that cooperates with the guide rail 7. Of course, the guide can be an optical axis, and the movable seat 8 is provided with a linear bearing sleeved on the optical axis. The driving device for driving the movable seat 8 to move can be an electric push rod, a cylinder, etc.

[0039] In order to improve the support stability of the support structure 11 to the assembled bolts 300, in a preferred embodiment, as Figure 1 As shown, the support structure 11 has a V-shaped support surface, and the support structure 11 can form a V-shaped support (clamping) for the bolt. Compared with the straight support structure 11, it is obvious that this can improve the stability of the bolt.

[0040] In addition, the drive motor 6 can also be a motor equipped with a torque sensor, which is a prior art motor, such as a motor used in an existing electric torque wrench, which can be directly purchased from the market. During the process of tightening the bolt, the drive motor 6 can stop rotating after the bolt torque reaches the technical requirement value, ensuring that the bolt torque reaches the target requirement and improving the assembly quality.

[0041] It should be noted that the whole system used by the supporting nut assembly mechanism and the bolt assembly mechanism to automatically complete the bolt and nut assembly operation also includes an intelligent vision system based on machine vision, so the support 1 and the bracket 5 are also provided with a camera 3. However, it should be noted that the position of the camera 3 is not limited to being provided on the support 1 and the bracket 5, and it can also be installed on a multi-degree-of-freedom robot arm.

[0042] Specific embodiments of the nut assembly mechanism in the present invention: The embodiment of the nut assembly mechanism is the nut assembly mechanism described in the above-mentioned bolt and nut assembly device embodiment, which will not be described in detail here.

[0043] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention is described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions recorded in the aforementioned embodiments without creative work, or replace some of the technical features therein with equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

Claims

1. A nut assembly mechanism, characterized in that: It includes a support, on which a nut anti-rotation part is fixed, the nut anti-rotation part has a nut groove for the assembled nut to enter and cooperate with the nut to stop rotation, a push rod is movably assembled on the support, the push rod is equipped with an elastic part for automatically returning to its position, a through hole is provided at the center of the nut groove for the push rod to pass through, and the outer circumference of the push rod is smaller than the inner diameter of the nut, when the elastic part is in a natural state, the push rod protrudes from the notch of the nut groove, and the protruding part can be inserted into the bolt hole of the assembled flange, and the elastic deformation stroke of the elastic part being compressed or stretched satisfies the withdrawal of the push rod from the nut groove.

2. The nut assembly mechanism according to claim 1, characterized in that: A fixed sleeve is installed on the support, a nut anti-rotation component is installed on the fixed sleeve, an elastic component is arranged inside the fixed sleeve, and one end of the push rod is located inside the fixed sleeve.

3. The nut assembly mechanism according to claim 2, characterized in that: The two ends of the fixed sleeve have different calibers, and it has a large diameter end and a small diameter end. The part of the push rod located inside the fixed sleeve is provided with a stop structure, and the stop structure cooperates with the small diameter end stop.

4. The nut assembly mechanism according to claim 3, characterized in that: The elastic member is a compression spring, one end of which is in contact with the support, and the other end of which is in contact with the stop structure, and a portion of the push rod penetrates into the compression spring.

5. A bolt and nut assembly device, comprising a bolt assembly mechanism and a nut assembly mechanism, wherein the bolt assembly mechanism comprises a bracket, a rotatable tightening head and a driving device for driving the tightening head to rotate are mounted on the bracket, and the tightening head is provided with a bolt tightening mechanism for picking up the assembled bolt and cooperating with the bolt to stop rotation, wherein the bolt assembly mechanism comprises a bracket, a rotatable tightening head and a driving device for driving the tightening head to rotate, and ... driving device for driving the tightening head to rotate, and a driving device for driving the tightening head to rotate, and a driving device for driving the tightening head to rotate, and a driving device for driving the tightening head to rotate, and a driving device for driving the tightening head to rotate, and a driving device for driving the tightening head to rotate, and a driving device for driving The nut assembly mechanism is the nut assembly mechanism described in any one of claims 1 to 4.

6. The bolt and nut assembly device according to claim 5, characterized in that: An auxiliary supporting structure is installed on the bracket, and the auxiliary supporting structure includes a moving seat that can move relative to the bracket and a driving device for driving the moving seat to move. A support rod is installed on the moving seat, and a supporting structure for supporting the bolt is provided on the support rod. The moving stroke of the moving seat satisfies the position where the support rod moves to the position where the supporting structure contacts the bolt support and the position where the support rod is completely separated from the bolt and avoids the bolt head.

7. The bolt and nut assembly device according to claim 6, characterized in that: The support rod is movably assembled on the moving seat, and an elastic body is connected between the support rod and the moving seat.

8. The bolt and nut assembly device according to claim 6, characterized in that: A guide piece is installed on the bracket and is located at the tightening head and extends in a direction perpendicular to the rotating axis of the tightening head. The movable seat is installed on the guide piece.

9. The bolt and nut assembly device according to any one of claims 6 to 8, characterized in that: The supporting structure has a V-shaped supporting surface.

10. The bolt and nut assembly device according to any one of claims 5 to 8, characterized in that: The driving device for driving the tightening head to rotate is a motor equipped with a torque sensor.

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