A tightening and loosening device and method for a blind cavity nut

Abstract

The present invention relates to the technical field of nut disassembly and assembly, and discloses a tightening and loosening device for blind cavity nuts, which includes a frame and a support plate. An outer shaft is installed at the bottom of the frame, an offset head is arranged at the end of the outer shaft, and a swing mechanism is arranged on one side of the frame; a tightening gun is installed on the support plate, the output end of the tightening gun is connected with an inner shaft, and the inner shaft is movably arranged inside the outer shaft; the pre-tightening of the nut by the inner shaft is achieved through torque transmission, and the tightening of the nut by the outer shaft is achieved by combining angle and torque, so as to improve the tightening accuracy of the nut and the consistency and stability of the tightening torques of different nuts; the present invention also discloses a method for tightening and loosening blind cavity nuts, and through this method, the tightening efficiency of the nut can be greatly improved, and it is ensured that the tightening torque meets the requirements of the tightening torque accuracy.

Description

Technical Field

[0001] The present invention relates to the technical field of nut disassembly and assembly, and particularly relates to a device and method for tightening and loosening blind cavity nuts. Background Art

[0002] The tightening process of nuts is directly related to the reliability and safety of connections. Especially in occasions where the assembly space is narrow, the tightening process is complex, and high tightening precision is required, such as in blind cavities like the engine shaft cavity, the operation of disassembling and assembling nuts is rather cumbersome. Currently, for tightening and loosening nuts in blind cavities, most are manually disassembled and assembled using wrenches. However, in the case of a narrow internal space, it is not only difficult to effectively turn the nut, the operation is inconvenient, but also it is easy to cause knock and damage to the inside of the blind cavity.

[0003] To solve the above problems, Chinese Patent with application number CN2022115221957 discloses a device for disassembling and assembling connecting nuts in an aeroengine shaft cavity to be applicable to tightening and loosening nuts in a relatively small assembly space. This device tightens and loosens nuts through a tightening gun connected to an offset head, and a gear-type sleeve at the end of the offset head tightens and loosens the nuts. However, the tightening precision of this device is low and often fails to meet the precision requirements of the thread tightening torque on aviation equipment (generally ±5%, or even ±3%); if the tightening torque is less than the lower limit of the required torque, it is easy to cause relative slip of the connected parts when stressed, and if the tightening torque is greater than the upper limit of the required torque, it is easy to cause plastic deformation and excessive elongation of the bolt. Both situations will cause the thread connection to fail.

[0004] The reasons for the tightening torque of the above device not meeting the tightening torque precision requirements are as follows:

[0005] (1) The manufacturing precision, backlash, elastic deformation, etc. of the gear set in the offset head will all affect the finally transmitted torque; moreover, a relatively long shaft is used to connect the tightening gun and the offset head, and when this shaft is stressed, it will introduce additional torsional deformation, affecting the stability of torque output.

[0006] (2) The friction of gear meshing, the friction between gears and bearings, the friction between bolts and nuts, and the friction between the connected parts and nuts will convert energy into heat, resulting in a deviation of the actually transmitted torque.

[0007] (3) The tightening process does not adopt the torque + rotation angle control method, and the control system does not establish a mathematical model for torque error compensation.

[0008] Based on this, we propose a device and method for tightening and loosening blind cavity nuts to be applicable to occasions with a narrow assembly space, a complex tightening process (such as tightening, loosening, and then tightening again), and high tightening precision requirements. Summary of the Invention

[0009] The object of the present invention is to overcome the deficiencies in the prior art and provide a tightening and loosening device and method for blind cavity nuts. By using a swinging tightening method and combining the torque plus rotation angle method to tighten the nuts, the error sources are eliminated, and the tightening accuracy of the nuts and the consistency and stability of the tightening torques of different nuts are improved.

[0010] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0011] In a first aspect, a tightening and loosening device for blind cavity nuts is provided, including a frame and a support plate capable of lifting relative to the frame. An outer shaft is installed at the bottom of the frame, and an offset head capable of flipping relative to the outer shaft is provided at the end of the outer shaft. Moreover, a swinging mechanism for driving the horizontal swing of the outer shaft is provided on one side of the frame; the offset head includes a box body connected to the outer shaft. A sleeve gear and a driving gear for driving the rotation of the sleeve gear are installed inside the box body, and one ends of both the driving gear and the sleeve gear extend to the outside of the box body; a tightening gun is installed on the support plate, and an inner shaft for driving the rotation of the driving gear is connected to the output end of the tightening gun, and the inner shaft is movably inserted into the outer shaft.

[0012] Optionally, a lifting plate, a sliding plate, a rotating plate, and a fixing plate are sequentially arranged below the frame; a rotating mechanism for driving the rotation of the rotating plate is provided on the fixing plate, a translation mechanism for driving the sliding plate to move horizontally is provided on the rotating plate, and a lifting mechanism for driving the lifting plate to move along the axial direction of the outer shaft is provided on the sliding plate; the frame is installed on the lifting plate, and the outer shaft sequentially passes through the lifting plate, the sliding plate, the rotating plate, and the fixing plate.

[0013] Optionally, the frame includes a bottom plate connected to the swinging mechanism. A gantry is fixedly installed on the bottom plate, and the support plate is located inside the gantry.

[0014] Optionally, the swinging mechanism includes a second telescopic component, a swing rod, a rotating shaft, and a bracket. The bracket is fixedly installed on the lifting plate. One end of the rotating shaft is rotatably connected to the bracket, and the other end is fixedly connected to the bottom plate; the second telescopic component is connected to the lifting plate, the swing rod is perpendicular to the rotating shaft, and one end of the swing rod is rotatably connected to the output end of the second telescopic component, and the other end is fixedly connected to the rotating shaft.

[0015] Optionally, a ratchet component for restricting the one-way rotation of the sleeve gear is provided on the box body. The ratchet component includes a ratchet and a shifting lever for reversing. The ratchet is connected to the sleeve gear, and one end of the shifting lever is connected to the reversing component.

[0016] Optionally, the commutation assembly includes a winding and unwinding motor and a spring oppositely arranged on both sides of the frame. The output end of the winding and unwinding motor is connected with a winding roller, a first soft rope is wound around the winding roller, and the end of the first soft rope is connected to the left side of the lever; one end of the spring is connected to the frame, the other end is connected with a second soft rope, and the end of the second soft rope is connected to the right side of the lever.

[0017] Optionally, the offset head is rotatably connected to the outer shaft through an adapter. A moving sleeve is slidably sleeved on the outer shaft. A connecting rod is rotatably installed on the moving sleeve. One end of the connecting rod is rotatably connected to the offset head, and a driving assembly for driving the moving sleeve to move axially is arranged on the frame.

[0018] Optionally, the driving assembly includes a driving plate located below the frame. A first telescopic assembly for driving the driving plate to move axially along the outer shaft is arranged on the frame, and the driving plate is fixedly connected to the moving sleeve through a pull rod.

[0019] In a second aspect, a method for tightening and loosening a blind cavity nut is provided. The tightening and loosening device for the blind cavity nut described in the first aspect is adopted, and the method includes the following steps:

[0020] S1. The frame moves downward so that the offset head at the end of the outer shaft enters the blind cavity.

[0021] S2. After the offset head enters the blind cavity, it flips to the horizontal state, and then the support plate moves downward so that the end of the inner shaft is in mating connection with the driving gear.

[0022] S3. After the sleeve gear of the offset head aligns with the nut to be tightened, the tightening gun drives the sleeve gear to rotate through the inner shaft to pre-tighten the nut.

[0023] S4. After pre-tightening, the swinging mechanism drives the outer shaft to swing so that the offset head rotates around the axis of the nut to tighten the nut.

[0024] S5. After the nut is tightened, the ratchet assembly commutes, the tightening gun drives the sleeve gear to rotate in the reverse direction through the inner shaft, and the swinging mechanism drives the offset head to swing in the reverse direction through the outer shaft to loosen the nut.

[0025] S6. When the nut is loosened to the specified torque, the ratchet assembly commutes again, and the offset head is driven to move through the inner shaft and the outer shaft to tighten the nut again.

[0026] S7. Steps S3 - S6 are sequentially repeated to complete the installation of the remaining nuts in the blind cavity.

[0027] Optionally, during the process that the sleeve gear of the offset head aligns with the nut to be tightened, it is realized through the linkage cooperation among the rotating mechanism, the translation mechanism and the lifting mechanism.

[0028] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0029] (1) In the present invention, the inner shaft is driven to rotate by a tightening gun, and the sleeve gear of the offset head is driven to rotate by torque to pre-tighten the nut to be tightened. The outer shaft is driven to rotate by a swinging mechanism to drive the overall swinging of the offset head, and the nut is tightened by combining the angle and torque, improving the tightening accuracy of the nut and the consistency and stability of the tightening torque of different nuts;

[0030] (2) In the present invention, the commutation of the ratchet assembly is realized through a commutation component, ensuring the smooth realization of the tightening and loosening functions of the device for the nut, and having high switching efficiency and good stability;

[0031] (3) In the present invention, the frame can be lifted, rotated and horizontally moved, thereby driving the offset head to quickly align with the nut to be tightened. The offset head can be longitudinally flipped and can penetrate into a narrow space for complex tightening processes;

[0032] (4) In the disassembly and assembly method proposed in the present invention, the tightening gun drives the inner shaft to pre-tighten the nut through the offset head, and the swinging mechanism drives the outer shaft to swing the offset head, and the nut is tightened by combining the angle and torque. Then the two rotate in the reverse direction to loosen the nut, and finally tighten it again; through this method, it can be ensured that the tightening torque meets the requirements of the tightening torque accuracy, improving the quality and efficiency of nut tightening. Brief Description of the Drawings

[0033] Figure 1 is a schematic structural diagram of the tightening and loosening device for blind cavity nuts in an embodiment of the present invention;

[0034] Figure 2 is a schematic side view structural diagram of the tightening and loosening device for blind cavity nuts in an embodiment of the present invention;

[0035] Figure 3 is a schematic structural diagram of the swinging mechanism in an embodiment of the present invention;

[0036] Figure 4 is a schematic structural diagram of the frame in an embodiment of the present invention;

[0037] Figure 5 is a schematic structural diagram of the offset head in an embodiment of the present invention;

[0038] Figure 6 is a schematic internal structural diagram of the offset head in an embodiment of the present invention;

[0039] Figure 7 is a schematic structural diagram of the drive assembly in an embodiment of the present invention;

[0040] Among them, 1. Frame; 101. Bottom plate; 102. Gantry; 103. Support plate; 2. Tightening gun; 201. Inner shaft; 3. Outer shaft;

[0041] 4. Offset head; 401. Box body; 402. Driving gear; 403. Sleeve gear; 404. Intermediate gear; 405. Ratchet assembly; 406. Endoscope probe;

[0042] 501. Adapter; 502. Link; 503. Moving sleeve; 504. Pull rod; 505. Driving assembly; 551. First telescopic assembly; 552. Driving plate; 553. First guide rod;

[0043] 6. Swing mechanism; 601. Second telescopic assembly; 602. Swing rod; 603. Rotating shaft; 604. Bracket;

[0044] 7. Fixed plate; 8. Rotating plate; 9. Sliding plate; 10. Lifting plate; 11. Engine workpiece simulation device; 12. First gear; 13. Second gear; 14. Third telescopic assembly; 15. Top plate; 16. Second guide rod; 17. Driving motor; 18. Lead screw; 19. Screwing member; 20. Pulley assembly; 21. Winding and unwinding motor; 22. Spring; 23. Winding roller. Detailed implementation mode

[0045] Now, the present invention will be further described in detail with reference to the accompanying drawings and embodiments. These drawings are all simplified schematic diagrams, only showing the basic structure of the present invention in a schematic way, so they only show the components related to the present invention. Embodiment 1

[0046] As Figure 1 and Figure 2 shown, a device for tightening and loosening a blind cavity nut includes a fixed plate 7, a rotating plate 8, a sliding plate 9, and a lifting plate 10 arranged in sequence from bottom to top. A frame 1 is installed on the lifting plate 10. A support plate 103 capable of lifting relative to it is installed inside the frame 1. The bottom of the frame 1 is fixedly installed with an outer shaft 3, and the end of the outer shaft 3 is provided with an offset head 4 capable of flipping relative to the outer shaft 3. A tightening gun 2 is fixedly installed on the support plate 103. The output end of the tightening gun 2 is connected with an inner shaft 201, and the inner shaft 201 is movably inserted into the outer shaft 3.

[0047] As described above, a rotating mechanism for driving the horizontal rotation of the rotating plate 8 is provided on the fixed plate 7, a translation mechanism for driving the sliding plate 9 to move horizontally is provided on the rotating plate 8, a lifting mechanism for driving the lifting plate 10 to move along the axial direction of the outer shaft 3 is provided on the sliding plate 9, and the outer shaft 3 sequentially passes through the lifting plate 10, the sliding plate 9, the rotating plate 8, and the fixed plate 7. A swinging mechanism 6 for driving the horizontal swinging of the outer shaft 3 is provided on one side of the frame 1, and the swinging mechanism 6 is installed on the lifting plate 10 and can lift and translate synchronously with the frame 1.

[0048] Among them, the frame 1 can not only lift axially, rotate around the axis, and move horizontally synchronously with the lifting plate 10, but also swing horizontally relative to the lifting plate 10 under the action of the swinging mechanism 6, while the support plate 103 can lift relative to the frame 1 to drive the inner shaft 201 to dock with the offset head 4 and pre-tighten the nut through torque.

[0049] Specifically, an engine workpiece simulation device 11 is provided below the fixed plate 7, which includes an engine simulation part, bolts and nuts, and a static torque sensor, and is used to simulate the tightening and loosening of the bolts and nuts inside the blind cavity of the engine by this device.

[0050] First, the frame 1 moves downward, drives the offset head 4 into the blind cavity of the engine through the outer shaft 3, then the offset head 4 flips from a state parallel to the outer shaft 3 to a horizontal state (perpendicular to the outer shaft 3), and then the offset head 4 is aligned with the nut to be tightened by the linkage cooperation between the rotating mechanism, the translation mechanism, and the lifting mechanism, and then the nut tightening process is completed by this device.

[0051] During the installation process, first pre-tighten the nut (using torque) with the tightening gun 2, the inner shaft 201, and the offset head 4, then tighten the nut (using the combination of angle and torque) through the swinging mechanism 6, the outer shaft 3, and the offset head 4. After tightening, the inner shaft 201 and the outer shaft 3 cooperate with each other to loosen the nut, and finally tighten the nut again to complete the tightening installation of one nut.

[0052] During the process of removing the nut, the nut can be loosened first through the swinging mechanism 6, the outer shaft 3, and the offset head 4, and then the nut can be removed from the bolt through the tightening gun 2, the inner shaft 201, and the offset head 4.

[0053] Such as Figure 5 and Figure 6As shown, the offset head 4 includes a box body 401, a driving gear 402, a sleeve gear 403, and a plurality of intermediate gears 404. The driving gear 402 and the sleeve gear 403 are respectively rotatably installed at two ends inside the box body 401, and a plurality of intermediate gears 404 are arranged between them. The driving gear 402, the sleeve gear 403, and the intermediate gears 404 mesh with each other and are arranged in a straight line. That is, the torque of the driving gear 402 can be transmitted to the sleeve gear 403 through the intermediate gears 404 to realize the rotational drive of the sleeve gear 403.

[0054] As described above, the box body 401 is formed by docking two end caps, upper and lower. The gears are rotatably installed between the upper and lower end caps. The shaft end of the driving gear 402 and the sleeve end of the sleeve gear 403 both extend to the outside of the box body 401. After the offset head 4 is flipped to the horizontal state, the shaft end of the driving gear 402 protrudes from the top of the box body 401, and the sleeve end of the sleeve gear 403 protrudes from the bottom of the box body 401.

[0055] Among them, one end of the box body 401 close to the driving gear 402 is rotatably connected to the outer shaft 3. An endoscope probe 406 is further provided at the bottom of the box body 401, and a display device is equipped outside for assisting the staff to observe the tightening condition in the blind cavity. The inner shaft 201 is used to drive the driving gear 402 to rotate.

[0056] An inner corner groove is formed at the shaft end of the driving gear 402, and the end of the inner shaft 201 is in a shape corresponding to the inner corner groove. After the support plate 103 moves downward, the end of the inner shaft 201 is embedded in the inner corner groove, so as to realize the transmission of the torque of the tightening gun 2 to the driving gear 402 through the inner shaft 201, and then the driving gear 402 drives the sleeve gear 403 to rotate through the intermediate gears 404.

[0057] In addition, a ratchet assembly 405 is further provided at the top of the box body 401. The ratchet assembly 405 is used to control the one-way rotation of the sleeve gear 403 to ensure that the torque and rotational torque can be smoothly applied to the nut. And the ratchet assembly 405 can also be reversed through a reversing assembly, which is convenient for realizing the tightening and loosening of the nut (that is, tightening and loosening).

[0058] As Figure 3 shown, the frame 1 includes a bottom plate 101 connected to the swing mechanism 6. A gantry 102 is fixedly installed on the bottom plate 101, and the support plate 103 is located inside the gantry 102. Both sides of the support plate 103 are slidably connected to the inside of the gantry 102 through slide rails, and an electric cylinder is installed on the gantry 102. The output end of the electric cylinder is fixedly connected to the support plate 103.

[0059] The swing mechanism 6 includes a second telescopic component 601, a swing rod 602, a rotating shaft 603 and a bracket 604. The bracket 604 is fixedly installed on the lifting plate 10. One end of the rotating shaft 603 is rotatably connected to the bracket 604, and the other end is fixedly connected to the bottom plate 101. The second telescopic component 601 is connected to the lifting plate 10 through a support column. The swing rod 602 is perpendicular to the rotating shaft 603. One end of the swing rod 602 is rotatably connected to the output end of the second telescopic component 601, and the other end is fixedly connected to the rotating shaft 603.

[0060] The second telescopic component 601 can adopt an electric cylinder. The telescopic movement of its output end can drive the rotating shaft 603 to rotate around its own axis through the swing rod 602. Since the rotating shaft 603 is fixedly connected to the bottom plate 101, the swing of the frame 1 is realized. The frame 1 then drives the outer shaft 3 to swing horizontally, so that the offset head 4 rotates horizontally around the axis of the sleeve gear 403, thereby ensuring that the tightening torque of the device meets the tightening torque accuracy requirements by combining torque and angle.

[0061] Among them, the bracket 604 adopts a gantry structure. The rotating shaft 603 and the outer shaft 3 are parallel to each other. The upper end of the rotating shaft 603 is rotatably connected to the bracket 604, and the middle part can be further connected to the bracket 604 through bearings, etc. The lower end is fixedly connected to the bottom plate 101 of the frame 1. That is, the whole frame 1 is connected to the lifting plate 10 through the rotating shaft 603 and the bracket 604. The second telescopic component 601 drives the rotating shaft 603 to rotate around its own axis through the swing rod 602, so that the frame 1 and the components thereon can swing horizontally around the axis of the rotating shaft 603, and at the same time drive the offset head 4 to swing around the axis of the sleeve gear 403 or the nut to be tightened, completing the tightening or loosening operation of the nut on the bolt.

[0062] Working principle:

[0063] First, install all the nuts to be tightened onto the bolts. The frame 1 moves downward, drives the offset head 4 to longitudinally enter the blind cavity of the engine through the outer shaft 3. Subsequently, the offset head 4 flips to the horizontal state, observes the position of the nut through the endoscope probe 406, and then makes the sleeve end of the sleeve gear 403 on the offset head 4 align with the nut to be tightened (that is, the sleeve is sleeved on the nut) by the linkage cooperation among the rotating mechanism, the translation mechanism and the lifting mechanism.

[0064] First, pre-tighten the nut through the tightening gun 2, the inner shaft 201 and the offset head 4, then tighten the nut through the swing mechanism 6, the outer shaft 3 and the offset head 4. After tightening, the inner shaft 201 and the outer shaft 3 cooperate with each other to loosen the nut, and finally tighten the nut again to complete the tightening installation of one nut. During the pre-tightening and tightening processes, the nut moves downward along the bolt axis, and at this time the lifting plate 10 also moves downward accordingly. Similarly, when loosening, the nut moves upward along the bolt axis, and the lifting plate 10 also moves upward accordingly.

[0065] When removing the nut, first loosen the nut, which will move upward along the axis of the bolt. At this time, the lifting plate 10 also moves upward accordingly until the nut is completely loosened, facilitating subsequent removal. Embodiment 2

[0066] As Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 shown, on the basis of Embodiment 1, the present invention also discloses the specific structures of the rotating mechanism, the translation mechanism and the lifting mechanism.

[0067] The rotating mechanism includes a connecting part, a first gear 12 and a second gear 13. The fixed plate 7 and the rotating plate 8 are rotatably connected through the connecting part. The first gear 12 is fixedly sleeved on the outside of the connecting part. The second gear 13 is rotatably installed on the rotating plate 8 and is driven to rotate by a motor. The first gear 12 and the second gear 13 mesh with each other, and the radial dimension of the first gear 12 is larger than the radial dimension of the second gear 13.

[0068] The connecting part is equivalent to a bearing. Its inner ring is fixedly connected to the rotating plate 8, and its outer ring is fixedly connected to the fixed plate 7. Moreover, the first gear 12 is fixedly sleeved on the outer ring. When the motor drives the second gear 13 to rotate, due to the meshing effect, the second gear 13 will drive the rotating plate 8 to rotate around the axis of the first gear 12, thus facilitating the offset head 4 to align with nuts at different positions on the circumference.

[0069] The translation mechanism includes a third telescopic component 14. The third telescopic component 14 is fixedly installed on the rotating plate 8, and the output end of the third telescopic component 14 is connected to the sliding plate 9. The sliding plate 9 and the rotating plate 8 are slidably connected through a guide rail and a slider. Moreover, the third telescopic component 14 can also adopt an electric cylinder. As its output end expands and contracts, the sliding plate 9 moves horizontally along the guide rail synchronously.

[0070] The lifting mechanism includes a second guide rod 16, a driving motor 17, a lead screw 18 and a screwing component 19. The screwing component 19 is fixedly installed on the lifting plate 10. One end of each of the plurality of second guide rods 16 is fixedly connected to the sliding plate 9, and the other end is fixedly connected through a top plate 15. The driving motor 17 is fixedly installed on the top plate 15. One end of the lead screw 18 is connected to the output end of the driving motor 17, and the other end is rotatably connected to the sliding plate 9. Moreover, the lead screw 18 is screwed through the screwing component 19.

[0071] Among them, the second guide rod 16, the lead screw 18 are parallel to the inner shaft 201 and the outer shaft 3. The driving motor 17 drives the lead screw 18 to rotate. Due to the screwing connection relationship, the screwing component 19 can drive the lifting plate 10 to reciprocate along the axis of the lead screw 18, thereby realizing the lifting function. Here, the screwing component 19 usually adopts a nut.

[0072] To ensure the stability of lifting, four second guide rods 16 are provided and distributed on the peripheral side of the frame 1, and the second guide rods 16 are connected to the lifting plate 10 through linear bearings.

[0073] As described above, the frame 1 is installed on the lifting plate 10. Through the coordinated action of the rotation mechanism, translation mechanism, and lifting mechanism, not only can the functions of translation, rotation, and lifting be achieved to quickly align with the nut to be tightened, but also under the action of the swing mechanism 6, the frame 1 can drive the outer shaft 3 to rotate around the rotating shaft 603, so that the offset head 4 tightens the nut in a manner combining torque and angle.

[0074] One end of the outer shaft 3 is fixedly connected to the bottom plate 101, and the other end passes through the lifting plate 10, sliding plate 9, rotating plate 8, and fixing plate 7. To ensure the smooth swing of the outer shaft 3, avoidance holes are provided on the lifting plate 10, sliding plate 9, rotating plate 8, and fixing plate 7. Embodiment III

[0075] Based on Embodiment I, the present invention also discloses the related structures of the ratchet assembly 405 and the commutation assembly.

[0076] As Figure 5 and Figure 6 shown, the ratchet assembly 405 includes a ratchet and a shift lever. The ratchet is connected to the sleeve gear 403 and is used to limit the one-way rotation of the sleeve gear 403 to facilitate tightening or loosening of the nut; the shift lever is used to change the direction allowing the sleeve gear 403 to rotate, and one end of the shift lever is connected to the commutation assembly.

[0077] As described above, by adjusting the position of the shift lever, the rotation direction of the ratchet can be changed. Since this structure is a prior art and is equivalent to a ratchet wrench, it will not be elaborated here; the commutation assembly here is used to adjust the position of the shift lever, thereby realizing the control of the rotation direction of the ratchet, which is convenient for the offset head 4 to perform the tightening and loosening operations on the nut in the blind cavity.

[0078] One end of the shift lever is rotatably connected to the main body of the ratchet assembly 405, and two holes are oppositely arranged at the other end for connecting the commutation assembly; for example, when the end of the shift lever rotates to the left, the forward rotation of the sleeve gear 403 can be blocked, so that the offset head 4 can tighten the nut; when the end of the shift lever rotates to the right, the reverse rotation of the sleeve gear 403 can be blocked, so that the offset head 4 can loosen the nut.

[0079] As Figure 3 and Figure 4As shown in the figure, the commutation assembly includes a winding and unwinding motor 21 and a spring 22. The winding and unwinding motor 21 and the spring 22 are oppositely arranged on both sides of the frame 1. The output end of the winding and unwinding motor 21 is connected to a winding roller 23. A first soft rope is wound around the winding roller 23, and the end of the first soft rope is connected to the hole on the left side of the lever. One end of the spring 22 is connected to the frame 1, and the other end is connected to a second soft rope, and the end of the second soft rope is connected to the hole on the right side of the lever.

[0080] Among them, the winding and unwinding motor 21 is fixed on the left side of the gantry 102. A screw rod is fixedly installed on the right side of the gantry 102. The end of the screw rod is fixedly connected to the upper end of the spring 22, and the lower end of the spring 22 is fixedly connected to the second soft rope.

[0081] Specifically, the winding and unwinding motor 21 winds the first soft rope through the winding roller 23. The first soft rope pulls the lever to swing to the left position, and the offset head 4 can rotate forward to tighten the nut. At the same time, the second soft rope on the right side is pulled by hand, driving the spring 22 to stretch and store elastic potential energy. When the winding and unwinding motor 21 unwinds the first soft rope through the winding roller 23, under the action of the elastic force of the spring 22, the lever swings back to the right position, and the offset head 4 can rotate reversely to loosen the nut.

[0082] Furthermore, in order to reduce the friction and wear between the soft rope and the equipment, pulley assemblies 20 are correspondingly arranged on the components through which the soft rope passes. The soft rope passes through the pulleys of the pulley assemblies 20, which can reduce the friction and wear and play a guiding role. For example, the pulley assemblies 20 are arranged on both sides of the gantry 102, and sensors for detecting the position of the soft rope are also arranged on both sides of the gantry 102 to ensure that the winding and unwinding motor 21 will not overwind. Embodiment Four

[0083] As Figure 5 and Figure 7 shown, on the basis of Embodiment One, the present invention also discloses a structure for realizing the longitudinal flipping of the offset head 4.

[0084] The offset head 4 is rotationally connected to the outer shaft 3 through an adapter 501. A moving sleeve 503 is slidably sleeved on the outer shaft 3. A connecting rod 502 is rotatably installed on the moving sleeve 503. One end of the connecting rod 502 is rotationally connected to the offset head 4, and a driving assembly 505 for driving the moving sleeve 503 to move axially is arranged on the frame 1.

[0085] Among them, the upper end of the connecting rod 502 is rotationally connected to the lower end of the moving sleeve 503, and the lower end of the connecting rod 502 is rotationally connected to one end of the box body 401 close to the driving gear 402. The adapter 501 includes a sleeve fixedly connected to the outer shaft 3. The inner side of the sleeve is rotationally connected to a rotating body through a pin shaft, and the pin shaft is perpendicular to the axis of the outer shaft 3. The shaft end of the driving gear 402 penetrates through the rotating body.

[0086] When the moving sleeve 503 moves upward, the offset head 4 is driven by the connecting rod 502 to flip around the pin shaft of the adapter 501 to a state parallel to the outer shaft 3. When the moving sleeve 503 moves downward, the offset head 4 is driven by the connecting rod 502 to flip to a horizontal state. At this time, the driving gear 402 is coaxial with the inner shaft 201.

[0087] The driving assembly 505 includes a first telescopic assembly 551, a driving plate 552, and a first guide rod 553. The first telescopic assembly 551 is fixedly installed on the bottom plate 101. The driving plate 552 is located below the bottom plate 101. The first guide rod 553 is slidably inserted through the bottom plate 101, and a limit block is provided at the upper end of the first guide rod 553, and the lower end is fixedly connected to the driving plate 552. The output end of the first telescopic assembly 551 passes through the bottom plate 101 and is fixedly connected to the driving plate 552.

[0088] Specifically, the first telescopic assembly 551 can drive the driving plate 552 to reciprocate along the axis of the first guide rod 553, and the driving plate 552 is fixedly connected to the moving sleeve 503 through a pull rod 504, that is, the moving sleeve 503 and the driving plate 552 can move synchronously under the drive of the first telescopic assembly 551.

[0089] Furthermore, the rear end of the driving plate 552 is connected to the first telescopic assembly 551 and the first guide rod 553. The front end has a bifurcated structure. The bifurcated structure is sleeved outside the outer shaft 3, and the pull rod 504 is fixed to the front end of the separated structure, so that the pull rod 504 and the outer shaft 3 are parallel to each other, ensuring the synchronism of the movement of the moving sleeve 503 and the driving plate 552.

[0090] In order to ensure that the moving sleeve 503 can smoothly slide along the outer shaft 3, two pull rods 504 are provided, which are relatively distributed on both sides of the outer shaft 3 to ensure the force balance of the moving sleeve 503.

[0091] In summary, the first telescopic assembly 551 can adopt an electric cylinder. Through the expansion and contraction of its output end, the moving sleeve 503 can be driven to move axially along the outer shaft 3 by using the driving plate 552 and the pull rod 504. Embodiment Five

[0092] On the basis of Embodiment One, Embodiment Two, Embodiment Three, and Embodiment Four, the present invention also proposes a method for tightening and loosening a blind cavity nut, which can realize the tightening process of the nut in a narrow space.

[0093] A method for tightening and loosening a blind cavity nut includes the following steps: First, all nuts are installed on the bolts inside the engine blind cavity. Then, the offset head 4 enters the blind cavity. Subsequently, the offset head 4 flips to a horizontal state. Then, by the linkage cooperation between the rotation mechanism, the translation mechanism, and the lifting mechanism, the sleeve gear 403 of the offset head 4 is aligned and sleeved on the nut to be tightened. Then, the nut is tightened onto the bolt by a process of pre-tightening, tightening, loosening, and then tightening.

[0094] During pre-tightening, the inner shaft 201 moves downward to dock with the driving gear 402, and then the tightening gun 2 is tightened to drive the inner shaft 201 to rotate. The torque of the inner shaft 201 is transmitted to the sleeve gear 403 through the driving gear 402 and the transition gear 404. The sleeve end of the sleeve gear 403 drives the nut to be pre-tightened to the set torque.

[0095] During the first tightening, the second telescopic component 601 of the swinging mechanism 6 drives the rotating shaft 603 to rotate around the swinging rod 602. The rotating shaft 603 then drives the outer shaft 3 to swing around the rotating shaft 603 through the bottom plate 101, and further drives the offset head 4 to rotate around the axis of the nut to be tightened, so as to tighten the nut to the specified torque in a combination of torque and angle, ensuring that the tightening torque of the equipment meets the requirements of the tightening torque accuracy.

[0096] When loosening, first, the ratchet assembly 405 changes the direction to ensure that the offset head 4 and the sleeve gear 403 inside it can rotate in the reverse direction. Then, the tightening gun 2 drives the inner shaft 201 to rotate in the reverse direction, and the swinging mechanism 6 drives the outer shaft 3 to swing in the reverse direction until the nut is loosened to the specified torque.

[0097] When tightening again, the ratchet assembly 405 changes the direction again to ensure that the offset head 4 and the sleeve gear 403 inside it can rotate in the forward direction. Then, the tightening gun 2 drives the inner shaft 201 to rotate in the forward direction, and the swinging mechanism 6 drives the outer shaft 3 to swing in the forward direction until the nut is finally tightened to the required torque.

[0098] Through pre-tightening, the first tightening, loosening and then tightening, the tightening and installation of one nut are completed. Subsequently, the remaining nuts are tightened in sequence according to the process requirements through the rotating mechanism, the translation mechanism and the lifting mechanism.

[0099] Before the offset head 4 enters the internal blind cavity of the engine, the offset head 4 is parallel to the outer shaft 3; the lifting mechanism drives the lifting plate 10 to move downward, and the frame 1 moves downward accordingly, so that the offset head 4 at the end of the outer shaft 3 enters the blind cavity.

[0100] After the offset head 4 enters the blind cavity, the first telescopic component 551 drives the moving sleeve 503 to move downward through the driving plate 552 and the pull rod 504, and the connecting rod 502 drives the offset head 4 to flip to the horizontal state. At this time, the offset head 4 is perpendicular to the outer shaft 3.

[0101] After the offset head 4 is in the horizontal state, the support plate 103 is driven by the electric cylinder to move downward until the end of the inner shaft 201 is in mating connection with the inner corner groove at the shaft end of the driving gear 402. At this time, the tightening gun 2 can transmit the torque to the driving gear 402 through the inner shaft 201, and then the driving gear 402 drives the sleeve gear 403 to rotate.

[0102] Among them, the lifting mechanism can drive the frame 1 to move up and down through the lifting plate 10 and the bracket 604. The translation mechanism can drive the sliding plate 9 to move horizontally. The rotation mechanism can drive the rotating plate 8 to rotate around the axis of the first gear 12. The first gear 12 is coaxial with the blind cavity of the engine. The lifting plate 10, the sliding plate 9 and the rotating plate 8 are connected in sequence. Thus, the rotation, translation and lifting of the outer shaft 3 can be realized. The offset head 4 is connected to the outer shaft 3. That is, the offset head 4 can be driven by the outer shaft 3 to align with different nuts in the blind cavity in sequence, and the tightening operation can be carried out on them in sequence.

[0103] In summary, a tightening and loosening device and method for blind cavity nuts proposed by the present invention uses the swing tightening method, and the tightening control strategy combines the torque and rotation angle method, which greatly eliminates most error sources, improves the tightening accuracy of the nuts and the consistency and stability of the tightening torques of different nuts. It has great popularization value for occasions with narrow space, complex tightening process and high torque accuracy requirements.

[0104] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It 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 therefore cannot be understood as a limitation of the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first", "second", etc. may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise specified, the meaning of "plurality" is two or more.

[0105] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "mounted", "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood through specific situations.

[0106] Based on the inspiration of the ideal embodiments of the present invention, through the above description, relevant personnel can completely make various changes and modifications without departing from the technical idea of the present invention. The technical scope of the present invention is not limited to the content in the specification, and the technical scope must be determined according to the scope of the claims.

Claims

1. A blind cavity nut tightening and loosening device, characterized in that: It comprises a frame (1) and a support plate (103) capable of rising and falling relative to the frame (1); an outer shaft (3) is installed at the bottom of the frame (1); an offset head (4) capable of flipping relative to the outer shaft (3) is arranged at the end of the outer shaft (3); and a swing mechanism (6) for driving the outer shaft (3) to swing horizontally is arranged on one side of the frame (1); The offset head (4) comprises a box body (401) connected to the outer shaft (3), a sleeve gear (403) and a driving gear (402) for driving the sleeve gear (403) to rotate are installed inside the box body (401), and one end of the driving gear (402) and the sleeve gear (403) both extend to the outside of the box body (401); A tightening gun (2) is mounted on the support plate (103); an output end of the tightening gun (2) is connected to an inner shaft (201) for driving the driving gear (402) to rotate, and the inner shaft (201) is movably inserted into the outer shaft (3); A lifting plate (10), a sliding plate (9), a rotating plate (8) and a fixed plate (7) are sequentially arranged below the frame (1); The fixed plate (7) is provided with a rotating mechanism for driving the rotating plate (8) to rotate, the rotating plate (8) is provided with a translation mechanism for driving the sliding plate (9) to move in a horizontal direction, and the sliding plate (9) is provided with a lifting mechanism for driving the lifting plate (10) to move in an axial direction of the outer shaft (3); The frame (1) is mounted on the lifting plate (10), and the outer shaft (3) passes through the lifting plate (10), the sliding plate (9), the rotating plate (8) and the fixed plate (7) in sequence; The box body (401) is provided with a ratchet assembly (405) for limiting the one-way rotation of the sleeve gear (403), the ratchet assembly (405) comprising a ratchet wheel and a lever for reversing, the ratchet wheel is connected to the sleeve gear (403), and one end of the lever is connected to the reversing assembly; The reversing assembly comprises a winding discharge motor (21) and a spring (22) arranged on two sides of the frame (1) relative to each other, the output end of the winding discharge motor (21) being connected to a winding roller (23), a first soft rope being wound around the winding roller (23), and an end of the first soft rope being connected to the left side of the shifting rod; one end of the spring (22) being connected to the frame (1), and the other end being connected to a second soft rope, and an end of the second soft rope being connected to the right side of the shifting rod.

2. The blind cavity nut tightening and loosening device according to claim 1, characterized in that: The frame (1) comprises a bottom plate (101) connected to the swing mechanism (6), a gantry (102) is fixedly mounted on the bottom plate (101), and the support plate (103) is located on the inner side of the gantry (102).

3. The blind cavity nut tightening and loosening device according to claim 2, characterized in that: The swing mechanism (6) comprises a second telescopic component (601), a swing rod (602), a rotating shaft (603) and a bracket (604); the bracket (604) is fixedly mounted on the lifting plate (10); one end of the rotating shaft (603) is rotatably connected to the bracket (604), and the other end is fixedly connected to the bottom plate (101); The second telescopic assembly (601) is connected to the lifting plate (10), the swing rod (602) is perpendicular to the rotating shaft (603), and one end of the swing rod (602) is rotatably connected to the output end of the second telescopic assembly (601), and the other end is fixedly connected to the rotating shaft (603).

4. The blind cavity nut tightening and loosening device according to claim 1, characterized in that: The offset head (4) is rotatably connected to the outer shaft (3) via an adapter (501); a movable sleeve (503) is slidably sleeved on the outer shaft (3); a connecting rod (502) is rotatably mounted on the movable sleeve (503); one end of the connecting rod (502) is rotatably connected to the offset head (4); and a driving component (505) for driving the movable sleeve (503) to move axially is provided on the frame (1).

5. The blind cavity nut tightening and loosening device according to claim 4, characterized in that: The driving assembly (505) comprises a driving plate (552) located below the frame (1); a first telescopic assembly (551) for driving the driving plate (552) to move axially along the outer shaft (3) is provided on the frame (1); and the driving plate (552) is fixedly connected to the moving sleeve (503) via a pull rod (504).

6. A method for tightening and loosening a blind cavity nut, using the blind cavity nut tightening and loosening device according to any one of claims 1 to 5, characterized in that: The steps include: S1, the frame (1) moves downward so that the offset head (4) at the end of the outer shaft (3) enters the blind cavity; S2, the offset head (4) enters the blind cavity and flips to a horizontal state, and then the support plate (103) moves downward, so that the end of the inner shaft (201) is mated with the driving gear (402); S3, after the sleeve gear (403) of the offset head (4) is aligned with the nut to be tightened, the tightening gun (2) drives the sleeve gear (403) to rotate through the inner shaft (201) to pre-tighten the nut; S4, after pre-tightening, the swing mechanism (6) drives the outer shaft (3) to swing, so that the offset head (4) rotates around the axis of the nut, thereby tightening the nut; S5. After the nut is tightened, the ratchet assembly (405) changes direction, the tightening gun (2) drives the sleeve gear (403) to rotate in the opposite direction through the inner shaft (201), and the swing mechanism (6) drives the offset head (4) to swing in the opposite direction through the outer shaft (3), thereby loosening the nut; S6, after the nut is loosened to a specified torque, the ratchet assembly (405) is reversed again, driving the offset head (4) to move through the inner shaft (201) and the outer shaft (3), and tightening the nut again; S7. Repeat steps S3 to S6 in sequence to complete the installation of the remaining nuts in the blind cavity.

7. The method for tightening and loosening a blind cavity nut according to claim 6, characterized in that: The process of aligning the sleeve gear (403) of the offset head (4) with the nut to be screwed is achieved through the linkage cooperation between the rotating mechanism, the translation mechanism and the lifting mechanism.

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