An automated assembly device for bolted connection structures

Abstract

This invention relates to an automated assembly device for bolted-connected components, belonging to the field of aerospace liquid rocket engine assembly and manufacturing. It includes a PLC control system, a component A feeding mechanism, a component A positioning mechanism, a component B assembly mechanism, a component B positioning and locking mechanism, a bolt assembly mechanism, a washer and nut feeding mechanism, a washer and nut assembly mechanism, and a vision inspection device for precise position adjustment of components A and B. Through the coordinated operation of the vision inspection device, the PLC control system, and the various components, automated and precise assembly of bolted-connected engine components can be achieved, solving the problems of low assembly efficiency and poor assembly consistency in current manual assembly processes, and improving the automation level of liquid rocket engine manufacturing.

Description

Technical Field

[0001] This invention belongs to the field of liquid rocket engine assembly and manufacturing technology, and relates to an automatic assembly device for components with bolted connection structures. Background Technology

[0002] Threaded connections are one of the main assembly methods for liquid rocket engines. Typically, attitude control engines use bolts, flat washers, and self-locking nuts to assemble and connect the two types of engine components. Currently, most engine threaded connections are assembled and tightened manually, which results in numerous tightening points, low assembly efficiency, and poor assembly consistency.

[0003] The difficulty in achieving automatic assembly and tightening lies in:

[0004] 1) When using threaded connections, two types of engine components are assembled and connected using bolts, flat washers, and self-locking nuts. This involves the coordinated assembly of at least five components. To achieve automated assembly, precise positioning and coordinated movement of these five components are required. Furthermore, due to the compact structure of the engine, the corresponding clamping and moving equipment must utilize minimal space for material placement, loading, and moving assembly.

[0005] 2) Taking the assembly of the thrust device and the base plate as an example, to achieve reliable assembly, three sets of bolts, washers, and nuts need to be installed and tightened. During torque tightening, the tightening needs to be done sequentially, in segments, and evenly. This means the tightening equipment needs to pre-tighten the nuts at three locations sequentially (approximately 70% of the quantified torque value), then locate the nut positions and angles at the pre-tightening completion point, and then tighten the three fasteners sequentially. Each time the tightening equipment tightens the nuts, a mechanism needs to be set up to back-tighten the bolts to prevent inaccurate torque. Developing a repeated tightening and back-tightening scheme under intermittent operation is extremely complex.

[0006] 3) During the sequential installation of the three sets of fasteners, in order to prevent the two assembly components from rotating when the second and third fasteners are tightened, a positioning mechanism needs to be set up when the first set of fasteners is pre-tightened to restrict the relative assembly position of the two assembly components from a range of 6 degrees of freedom.

[0007] After searching, no other disclosed automatic assembly devices capable of realizing the above automatic assembly process were found. With the goal of solving the above assembly process, this invention proposes an automatic assembly device for components of bolted connection structures. Summary of the Invention

[0008] The technical problem solved by this invention is to overcome the shortcomings of the prior art and propose an automatic assembly device for bolted connection structures. It provides a device and method for repeated tightening and back-tightening of multiple fasteners, avoiding the phenomenon that the two assembly components rotate when multiple fasteners are tightened, thereby improving efficiency, saving resources, and ensuring assembly accuracy.

[0009] The solution of the present invention is: an automatic assembly device for components in a bolted connection structure, used to connect component B to component A through N sets of bolts, flat washers, and nuts; characterized in that it includes: a component B assembly mechanism, a component B positioning and locking mechanism, a bolt assembly mechanism, a flat washer assembly mechanism, and a nut assembly mechanism, where N>1;

[0010] The positioning and locking mechanism of component B includes a locking part, which has a second gripper and N-1 guide positioning pins. The guide positioning pins are positioned to correspond to the mounting holes of component B and can extend and retract along the Z-axis of the geodetic coordinate system. The second gripper is used to grasp and lock component B, fixing the X, Y, and Z degrees of freedom of component B in the geodetic coordinate system, as well as the rotational degree of freedom α about the X-axis and the rotational degree of freedom γ about the Y-axis. The N-1 guide positioning pins are used to insert into the N-1 mounting holes of component B, fixing the rotational degree of freedom β about the Z-axis of component B.

[0011] The component B assembly mechanism is used to clamp component B and move it to the target installation position until the axes of the N mounting holes of component A and the N mounting holes of component B are all coincident.

[0012] A bolt assembly mechanism is used to clamp the bolt and move it to the underside of component B, through the mounting hole without a guide locating pin, and to keep the bolt head in a tightened state.

[0013] A flat washer assembly mechanism is used to clamp the flat washer and insert it into the bolt after the bolt is assembled.

[0014] The nut assembly mechanism is used to cooperate with the bolt assembly mechanism after the flat washer is assembled. Under the back tightening action of the bolt assembly mechanism on the bolt, the nut is tightened onto the external thread of the bolt.

[0015] Furthermore, the locking part is also equipped with a pen-shaped cylinder, which is connected to the guide positioning pin and drives the guide positioning pin to extend and retract along the Z-axis of the geodetic coordinate system; before assembling the next bolt, the pen-shaped cylinder drives the guide positioning pin inserted into the corresponding mounting hole to lift up.

[0016] Furthermore, the component B assembly mechanism includes a first collaborative robot and a flexible fixture, the flexible fixture having a component B clamping part and being assembled at the end of the first collaborative robot.

[0017] Furthermore, at the connection point between the flexible fixture and the first collaborative robot, a bolt clamping part and a bolt back-tightening part are provided in a plane perpendicular to the clamping part of component B. The bolt clamping part and the bolt back-tightening part are respectively connected to the two ends of the clamping part of component B, and are used to integrate the functions of bolt clamping and back-tightening on the assembly mechanism of component B. When the flexible fixture switches from the clamping part of component B to the bolt clamping part to work, the assembly mechanism of component B is used as a bolt assembly mechanism.

[0018] Furthermore, the clamping part of component B includes a gripper, a first cylinder, and a pressure sensor;

[0019] The gripper is used to hold component B in motion. The first cylinder drives the gripper to open and close. The pressure sensor is located on the side wall of the gripper. When the gripper holds component B, the pressure sensor sends a pressure signal to confirm that component B is clamped.

[0020] Furthermore, the bolt clamping part includes bolt clamps, a second cylinder, and a spring;

[0021] The bolt clamps match the bolt head, the second cylinder drives the bolt clamps to hold, and the spring drives the bolt clamps to release.

[0022] The bolt back tightening part adopts a sleeve structure, and the end of the sleeve structure has a cavity, the shape of which matches the bolt head.

[0023] Furthermore, the nut assembly mechanism includes a third collaborative robot, the end of which is fixed with a tightening part;

[0024] The tightening part adopts a combination of a tightening shaft and a sleeve structure. The end of the tightening shaft is connected to the sleeve structure, which is fitted onto the nut for nut loading. The tightening shaft has a torque sensor to tighten the nut according to the torque requirements.

[0025] Furthermore, the tightening of the nut onto the external thread of the bolt under the back-tightening action of the bolt assembly mechanism specifically includes:

[0026] When assembling nuts, the nut pre-tightening operation is performed first. The tightening part of the nut assembly mechanism is used to tighten one end of the nut, while the bolt clamping part is pressed against the bolt head for fixation. When the pre-tightening torque is reached, the tightening part stops rotating, and the next nut pre-tightening is performed.

[0027] After all nuts are pre-tightened, the flexible fixture switches the bolt back-tightening part to work. The bolt back-tightening part moves to the bolt installation position and presses against the bolt head. When the nut end is rotated to tighten, the bolt rotates accordingly. When the bolt head rotates to a position where the cavity of the bolt back-tightening part can be inserted, the bolt back-tightening part performs the back-tightening action. The tightening part of the nut assembly mechanism completes the formal tightening according to the rotation angle recorded when the pre-tightening is completed.

[0028] Furthermore, it also includes a flat gasket feeding mechanism, which includes an axial feed column, a first pressing plate, a first locking nut, a first feeding cylinder, a first feeding plate, a blow-off air pipe, and a first slider.

[0029] The first clamping plate contacts the upper surface of the first slider, and the first locking nut is set on the upper surface of the first clamping plate to apply a clamping force to the first clamping plate. The bottom of the axial material column is installed on the upper surface of the first slider, and the first feeding plate is set at the bottom of the axial material column. The first feeding cylinder is fixedly connected below the first feeding plate and controls the first feeding plate to move and feed along the Z-axis of the geodetic coordinate system. The blowing air pipe is set on one side of the axial material column, and its blowing end faces the end of the axial material column. The flat gasket feeding mechanism allows the flat gasket assembly mechanism to take the flat gasket from the upper end of the axial material column.

[0030] Furthermore, it also includes a nut feeding mechanism, which includes an axial material groove, a second pressure plate, a second locking nut, a second feeding cylinder, a second material feeding plate, and a second slider;

[0031] The second clamping plate contacts the upper surface of the second slider, and the second locking nut is set on the upper surface of the second clamping plate to apply a clamping force to the second clamping plate. The bottom of the axial material groove is installed on the upper surface of the second slider, and the second feeding plate is set at the bottom of the axial material groove. The second feeding cylinder is fixed below the second feeding plate to control the second feeding plate to move the height of one nut along the axial direction each time. The nut feeding mechanism allows the nut assembly mechanism to take the nut from the upper end of the axial material groove.

[0032] The beneficial effects of this invention compared to the prior art are:

[0033] (1) The present invention overcomes the problem that the current automatic docking and tightening technology cannot meet the process requirements of symmetrical and uniform tightening by designing and arranging the component A feeding mechanism, component A positioning mechanism, component B assembly mechanism, component B positioning and locking mechanism, bolt assembly mechanism, flat washer and nut feeding mechanism, and flat washer and nut assembly mechanism. Under the premise of meeting the process requirements, it can replace manual assembly, improve assembly efficiency and consistency, and improve the automation level of liquid rocket engine production and manufacturing.

[0034] (2) The present invention designs a flexible fixture that integrates component B clamping function, bolt clamping function and bolt back tightening function. By switching the currently working gripper, different stages of installation operation can be achieved, saving the overall space of the automatic assembly device.

[0035] (3) The present invention provides a method for sequential, segmented and uniform assembly of nuts based on the designed flexible fixture. Each time the nuts are tightened by the tightening equipment, the bolt clamping part sends the bolt to the target installation position and then back-tightens the bolt to prevent inaccurate torque. After each nut is pre-tightened, the bolt back-tightening part is switched to apply the formal tightening torque, which further realizes the accuracy guarantee of the tightening torque.

[0036] (4) The present invention has made a clever design to the locking part in the positioning and locking mechanism of component B. When the various parts of the claw-shaped gripper clamp component B, the component B is locked in the X, Y, Z degrees of freedom and the rotational degree of freedom α about the X axis and the rotational degree of freedom γ about the Y axis. N-1 guide positioning pins are set on the outer periphery of the gripper. When the guide positioning pins are inserted into the mounting hole of component B, the component B is locked in the rotational degree of freedom β about the Z axis. This avoids the phenomenon that the two assembly components rotate when multiple fasteners are tightened, and improves the assembly accuracy.

[0037] (5) The flat washer feeding mechanism and the nut feeding mechanism designed in this invention are both axially distributed. To facilitate feeding, they are set up with a structure similar to a "clamp". Compared with the material tray feeding structure in the prior art, the feeding space is fully saved. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the threaded connection between the engine base plate and the thrust device in an embodiment of the present invention;

[0039] Figure 2 This is a structural diagram of the automatic assembly device for components A and B according to an embodiment of the present invention;

[0040] Figure 3 This is a schematic diagram of the feeding mechanism of component A in an embodiment of the present invention;

[0041] Figure 4 This is a schematic diagram of the positioning mechanism of component A in an embodiment of the present invention;

[0042] Figure 5 This is a schematic diagram of the locking mechanism structure of component A in an embodiment of the present invention;

[0043] Figure 6 This is a schematic diagram of the assembly mechanism of component B in an embodiment of the present invention;

[0044] Figure 7 This is a schematic diagram of component B and the flexible jig for bolt assembly in an embodiment of the present invention;

[0045] Figure 8 This is a schematic diagram of component B and the bolt holder in an embodiment of the present invention;

[0046] Figure 9 This is a schematic diagram of the positioning and locking mechanism of component B in an embodiment of the present invention;

[0047] Figure 10 This is a schematic diagram of the flat gasket feeding mechanism according to an embodiment of the present invention;

[0048] Figure 11 This is a schematic diagram of the flat gasket assembly mechanism according to an embodiment of the present invention;

[0049] Figure 12 This is a schematic diagram of the nut feeding mechanism according to an embodiment of the present invention;

[0050] Figure 13 This is a schematic diagram of the nut assembly mechanism according to an embodiment of the present invention.

[0051] Explanation of reference numerals in the attached diagram:

[0052] 201-Engine base plate; 202-Thrust assembly; 203-Bolt; 204-Flat washer; 205-Self-locking nut; 206-Light-transmitting hole in base plate;

[0053] 1-Component A feeding mechanism; 2-Component A positioning mechanism; 3-Component B assembly mechanism; 4-Component B positioning and locking mechanism;

[0054] 5- Bolt assembly mechanism; 6- Flat washer feeding mechanism; 7- Flat washer assembly mechanism; 8- Nut feeding mechanism; 9- Nut assembly mechanism;

[0055] 10 - Component B rack; 11 - Conveyor belt; 12 - Component A position detection device; 13 - Component B position detection device Detailed Implementation

[0056] The invention will now be further described with reference to the accompanying drawings.

[0057] like Figure 1 (a) Figure 1 As shown in (b), this embodiment is applied to the assembly of the engine base plate 201 and the thrust device 02. The thrust device 02 is provided with three mounting holes, which are respectively connected to the three mounting holes of the engine base plate by bolts 203, flat washers 204, and self-locking nuts 205, as follows. Figure 1 (c)~ Figure 1 As shown in (e). The thrust device 02 installed on the base plate 201 is divided into three types according to the angle between the electrical interface axis and the nozzle axis, and is strictly assembled according to the corresponding assembly position relationship.

[0058] It should be noted that in this embodiment, component A represents the engine base plate 201, and component B represents the thrust device 02. The assembly method is that the mounting holes of the three lugs of the thrust device are aligned with the mounting holes of the base plate, the bolts 203 are inserted from the bottom of the base plate, the flat washers 204 are inserted from the top, and the self-locking nuts 205 are installed from the top and pre-tightened. The assembly and pre-tightening of the three fasteners are completed in sequence according to the above steps. Then, the three self-locking nuts 205 are tightened in sequence according to the torque requirements, thus completing the assembly of the thrust device and the engine base plate.

[0059] like Figure 2 The diagram illustrates an application example of an automated assembly device for bolted connection structures in the assembly process of an engine thrust unit. The automated assembly device is integrated into a single cabinet and consists of three stations: Station I (component A loading station), Station II (thrust unit assembly station), and Station III (component B, bolt, flat washer, and nut loading station). Specifically, Station I includes a component A loading mechanism 1 and a component B positioning and locking mechanism 4; Station II includes a component A positioning mechanism 2, a nut assembly mechanism 9, and a component A position detection device 12; Station III includes a component B assembly mechanism 3, a bolt assembly mechanism 5, a flat washer loading mechanism 6, a flat washer assembly mechanism 7, a nut loading mechanism 8, a component B rack 10, a bolt rack 3224, and a component B position detection device 13. A PLC is selected as the control system.

[0060] In this embodiment, the selected coordinate system XYZ is the geodetic coordinate system, wherein the rotational degree of freedom about the X-axis is α, the rotational degree of freedom about the Y-axis is γ, and the rotational degree of freedom about the Z-axis is β.

[0061] The component A feeding mechanism 1 completes the conveying and initial positioning of component A, such as Figure 3 As shown, it consists of a conveyor belt 11, a limiting mechanism 130, a lifting mechanism 14, and a transmission motor 15. Component A flows on the conveyor belt 11. The limiting mechanism 130 is controlled by the lower cylinder 131 to extend and retract in the Z direction, stopping component A at the assembly station. The lifting mechanism 14, driven by the lifting motor 141, is located below the conveyor belt 11, lifting component A to the gripping position of the component A positioning mechanism 2.

[0062] like Figure 4 As shown, the component A positioning mechanism 2 is equipped with a component A clamping mechanism 21 and a component A locking mechanism 22. In this embodiment, component A is a hollow disc. The component A clamping mechanism 21 is a three-jaw chuck 212 driven by a cylinder 211. The jaws are stepped, and the outer arc surface of the jaws opens and positions the bottom plate through the central hole of component A. The jaw steps provide bottom support for component A, thereby restricting the X, Y, and Z degrees of freedom of component A. The cylinder 211 lifts component A to the assembly position.

[0063] The component A position detection device 12 is an infrared detection device. An infrared signal transmitter 121 is installed below the conveyor belt 11 of the component A feeding mechanism 1, and an infrared signal receiver 122 is fixed above the component A positioning mechanism 2. The component A clamping mechanism 21 is driven by the upper motor 213 to rotate the component A. When the infrared signal is detected by the infrared signal receiver 122 through the light-transmitting hole 206 on the bottom plate, the PLC receives the signal and controls the motor 213 of the component A clamping mechanism to stop rotating. At this time, the component A locking mechanism 22 descends, and its pressure plate 221 moves downward under the drive of the pen-shaped cylinder 223 to press and fix the component A, further preventing the component A from moving in the Z direction; at the same time, the sliding pin 222 is inserted into the circumferential positioning hole of the component A itself, completing the restriction of the component A in the α, β, and γ degrees of freedom. Thus, the component A positioning mechanism 2 completes the positioning and locking of the component A in six degrees of freedom. The structure of the component A locking mechanism 22 is as follows. Figure 5 As shown.

[0064] The assembly mechanism 3 of component B is as follows Figure 6 As shown, it includes a six-axis collaborative robot 31 and a flexible fixture 32. The flexible fixture 32 is equipped with three sets of clamping parts, such as... Figure 7 As shown, in this embodiment, the flexible fixture 32 is provided with a component B clamping part 321, and a bolt clamping part 322 and a bolt back tightening part 323 are also provided in the plane perpendicular to the component B clamping part 321. Among them, the bolt back tightening part 323 adopts a sleeve structure, and the end of the sleeve structure has a cavity, the shape of which matches the bolt head; both the component B clamping part 321 and the bolt clamping part 322 are clamping structures.

[0065] like Figure 7 As shown, the clamping part 321 of component B is driven by the first cylinder 3211 to open and close the gripper. A pressure sensor 3212 is provided on the side wall of the gripper. When the gripper clamps component B, the pressure sensor 3212 feeds back a pressure signal to confirm that component B is clamped. A non-metallic protective pad 3213 is provided at the contact part between the gripper and component B to prevent the gripper from causing pressure damage or indentation to component B.

[0066] The bolt clamping part 322 is clamped by the bolt jaws 3223 driven by the second cylinder 3221, and released by the bolt jaws 3223 driven by the spring 3222. Correspondingly, bolt jaws 3223 and bolt holders 3224 matching the hexagonal head bolts used in this embodiment are provided. See bolt holder 3224. Figure 8 (b).

[0067] When the flexible fixture 32 switches from the component B clamping part 321 to the bolt clamping part 322 to work, the component B assembly mechanism 3 is used as the bolt assembly mechanism 5.

[0068] In this embodiment, three different thrust devices need to be assembled on component A. Specifically, the nozzle axis of the three thrust devices is at 0°, 120°, and 240° angles to the electrical interface axis, respectively. For the three assembly configurations of component B, the component B material rack 10 is configured as a component B error-proof material rack 3215. Different opening directions of the error-proof material rack are set according to the angle between the nozzle axis and the electrical interface axis of component B, such as... Figure 8 As shown in (a).

[0069] During assembly, the six-axis collaborative robot 31 of the component B assembly mechanism 3 moves to the position of the component B error prevention rack 3215 to clamp the component B, and then moves to the position detection device 13 of the component B to take a picture. The installation hole position deviation is fed back to the PLC, and after compensating for the target coordinates, it moves to the assembly position.

[0070] At this time, the positioning and locking mechanism 4 of component B restricts the X, Y, Z, α, β, and γ degrees of freedom of component B, and its structure is as follows. Figure 9 As shown. Component B positioning and locking mechanism includes a locking part 41, a moving motor 42, a moving conveyor chain 43, and a rotating motor 44.

[0071] The mobile motor 42 drives the mobile conveyor chain 43 to move the locking part 41 in the XOY plane, and the rotary motor 44 is set in the mounting plane of the locking part 41 to drive the locking part 41 to rotate along the Z axis.

[0072] The locking part 41 is provided with a second gripper 411, a gripper drive cylinder 412, two guide positioning pins 413, and a pen-shaped cylinder 414 for extending and retracting the guide positioning pins along the Z-axis. In this embodiment, the second gripper 411 is composed of three L-shaped strip structures. When the second gripper 411 grips and locks the component B, it locks the component B in the X, Y, and Z degrees of freedom, as well as the rotational degree of freedom α about the X-axis and the rotational degree of freedom γ about the Y-axis.

[0073] Two guide positioning pins 413 are set on the outer periphery of the second gripper 411. When the guide positioning pins 413 are inserted into the mounting hole of component B, the component B is locked in rotational freedom β around the Z axis.

[0074] The number of guide positioning pins 413 is one less than the number of mounting holes of component B. After component B is assembled in place, the second gripper 411 fixes the position of component B. The two guide positioning pins 413 are respectively inserted into the two mounting holes after component A and component B are aligned, so as to control the alignment of the mounting hole axis when component A and component B are assembled.

[0075] A gripper drive cylinder 412 is connected to the upper end of the second gripper 411, driving the second gripper 411 to perform a gripping operation. A pen-shaped cylinder 414 is connected to a guide positioning pin 413, driving the guide positioning pin 413 to extend and retract along the Z-axis. When it is necessary to assemble the next nut, the pen-shaped cylinder 414 drives the guide positioning pin 413, which is inserted into the corresponding mounting hole, to lift.

[0076] The inner sides of the three L-shaped strip structures of the second gripper 411 are provided with guide grooves 415 to avoid interference with the electrical interface of component B during clamping.

[0077] After component B is locked and positioned, the component B clamping part 321 of the flexible fixture 32 is released, and the six-axis collaborative robot 31 moves to above the bolt rack 3224. The flexible fixture 32 switches to the bolt clamping part 322, which clamps the bolt from the bolt rack 3224 and moves it to a mounting hole below where the guide positioning pin 413 is inserted and inserts it. At this time, the six-axis collaborative robot 31 maintains its current position, and the bolt clamping part 322 keeps the bolt clamped.

[0078] like Figure 10 As shown, the flat gasket feeding mechanism 6 consists of an axial feed column 61, a first pressing plate 62, a first locking nut 63, a first feeding cylinder 64, a first feeding plate 65, a first slider 67, and a blow-off pipe 66.

[0079] The first clamping plate 62 contacts the upper surface of the first slider 67. The first locking nut 63 is set on the upper surface of the first clamping plate 62 to apply a clamping force to the first clamping plate 62. The bottom of the axial material column 61 is installed on the upper surface of the first slider 67. The first feeding plate 65 is set at the bottom of the axial material column 61. The first feeding cylinder 64 is fixedly connected below the first feeding plate 65 to control the first feeding plate 65 to move along the Z-axis to feed material. The blow-off pipe 66 is set on one side of the axial material column 61, with its blow-off end facing the end of the axial material column 61 to prevent the flat gasket from sticking due to oil stains on the surface of the flat gasket.

[0080] The flat gasket filling can be carried out without removing the axial material column 61, or by loosening the first locking nut 63 and the first clamping plate 62, removing the first slider 67, and then filling. When feeding the flat gasket 204, the feeding of one flat gasket is completed at a time by controlling the movement displacement of the first feeding plate 65.

[0081] like Figure 11As shown, the flat gasket assembly mechanism 7 includes a first four-axis collaborative robot 71, a first vision positioning device 72, and a gripping fixture 73. Both the first vision positioning device 72 and the gripping fixture 73 are located at the end of the first four-axis collaborative robot 71. The gripping fixture 73 is a sleeve structure and is equipped with a vacuum generator 74 to pick up the flat gasket. The first four-axis collaborative robot 71 drives the gripping fixture 73 to reach above the axial material column 61 of the flat gasket. The vacuum generator 74 operates to cause the gripping fixture 73 to pick up the flat gasket, move the flat gasket above the bolt, and then blow air through the vacuum generator 74 to insert the flat gasket into the bolt.

[0082] like Figure 12 As shown, the nut feeding mechanism 8 consists of an axial material groove 81, a second pressing plate 82, a second locking nut 83, a second feeding cylinder 84, a second feeding piece 85, and a second slider 86.

[0083] The second clamping plate 82 contacts the upper surface of the second slider 86, the second locking nut 83 is set on the upper surface of the second clamping plate 82, and applies a fastening force to the second clamping plate 82. The bottom of the axial material groove 81 is installed on the upper surface of the second slider 86, the second material feeding plate 85 is set at the bottom of the axial material groove 81, and the second feeding cylinder 84 is fixed below the second material feeding plate 85, controlling the second material feeding plate 85 to move axially by the height of one nut each time.

[0084] When filling the nuts, loosen the second locking nut 83, remove the second clamping plate 82, slide the axial material groove 81 along the second slider 86, and then fill the self-locking nut 205. After filling, install the second clamping plate 82 and the second locking nut 83 in sequence. During feeding, the axial displacement of the second feeding plate 85 is limited by the second feeding cylinder 84 to control the feeding of one nut at a time.

[0085] The structure of the automatic nut assembly mechanism 9 is as follows: Figure 13 As shown, the assembly includes a second four-axis collaborative robot 91, a second vision positioning device 92, and a tightening unit 93. The second vision positioning device 92 and the tightening unit 93 are fixed to the end of the second four-axis collaborative robot 91. The tightening unit 93 is a combination assembly of a tightening shaft and a sleeve structure. The end of the tightening shaft is connected to the sleeve structure, which is fitted onto the nut for nut picking. The tightening shaft has a torque sensor for tightening the nut according to the torque requirements. During assembly, the four-axis collaborative robot 91 drives the tightening unit 93 to the nut axial groove 81. After the tightening unit 93 returns to zero, it moves downwards to pick up the nut, moving it to the target assembly position. The tightening unit motor rotates to screw the nut into the bolt thread. During the tightening process, the bolt clamping part 322 of the clamping fixture 32 maintains the bolt clamped, providing back tightening for the nut tightening process.

[0086] It should be further explained that the automatic assembly process in this embodiment is consistent with the requirements of the manual assembly process. Specifically, for the three fasteners of a single component B, the nuts are first pre-tightened sequentially, with a pre-tightening force of approximately 70% of the tightening force. Then, the three fasteners are tightened sequentially with torque. During the tightening process, the bolt heads are reliably tightened by the bolt backing part 323 of the flexible fixture 32. The specific operation method is as follows:

[0087] When assembling nuts, the nut pre-tightening operation is performed first. The tightening part 93 of the nut assembly mechanism 9 tightens one end of the nut, while the bolt clamping part 322 presses against the bolt head for fixation. When the pre-tightening torque is reached, the tightening part 93 stops rotating and the next nut pre-tightening is performed.

[0088] After all nuts are pre-tightened, the flexible fixture 32 switches the bolt back-tightening part 323 to work. The bolt back-tightening part 323 moves to the bolt installation position and presses against the bolt head. When the nut end is rotated to tighten, the bolt rotates accordingly. When the bolt head rotates to a position where the cavity of the bolt back-tightening part 323 can be inserted, the bolt back-tightening part 323 performs the back-tightening action. The tightening part 93 of the nut assembly mechanism 9 completes the formal tightening according to the rotation angle recorded when the pre-tightening is completed.

[0089] This embodiment provides a method for calibrating the assembly positions of bolts 203, flat washers 204, and self-locking nuts 205 for components A (base plate) and B (thrust device):

[0090] The component A position detection device 12 is an infrared photoelectric sensor used to identify whether the base plate has been rotated to the set assembly angle. The component B position detection device 13 is used to obtain the center coordinates of the top circumference of the thrust device after clamping at the detection position, the center coordinates of its own mounting hole, and the center point coordinates of the bolt end face in the horizontal clamping state. The first visual positioning device 72 is used to obtain the center coordinates of the thrust device base plate insertion hole and the center coordinates of the thrust device base plate mounting hole after the base plate is fixed. The second visual positioning device 92 is used to obtain the center coordinates of the top circumference of the bolt after assembly.

[0091] (a) When the base plate reaches the assembly position, the positioning mechanism 2 of component A rotates the base plate.

[0092] (b) When the infrared signal is detected by the infrared signal receiver 122 through the light-transmitting hole 206 on the base plate, the motor 213 of the clamping mechanism of the PLC receiving signal control component A stops rotating and locks component A.

[0093] (c) The PLC-driven assembly mechanism 3 of component B grabs the thrust device from the component B anti-mistake rack 3215 and arrives at the shooting range of component B position detection device 13 according to the predetermined program trajectory; in this embodiment, component B position detection device 13 is fixed on the system truss and its position remains unchanged.

[0094] (d) Take a picture from the top of the thrust device using the component B position detection device 13 to obtain the center coordinates of the top circumferential features of the thrust device after clamping and the three mounting holes of the thrust device itself, and feed the center coordinates back to the PLC.

[0095] (e) The PLC drives the first four-axis collaborative robot 71 to reach the top of the base plate according to the predetermined program trajectory. The first vision positioning device 72 takes a picture of the thrust device installation area after the base plate is positioned, obtains the center coordinates of the thrust device base plate insertion hole and the three mounting holes on the base plate, and feeds the coordinate information back to the PLC.

[0096] (f) The PLC control system calculates the coordinates obtained by the component B position detection device 13 and the first vision positioning device 72 to obtain the coordinates of the center point of the top circumferential feature after the thrust device is clamped, the thrust device's own No. 1 mounting hole, the thrust device's bottom plate insertion hole, and the bottom plate's No. 1 mounting hole. It calculates the deviation {ΔX1, ΔY1} between the actual center coordinates of the thrust device's bottom plate insertion hole and the corresponding preset center coordinates in the X and Y directions. Simultaneously, it calculates the deviation {ΔX2, ΔY2} between the actual center coordinates of the top circumferential feature after the thrust device is clamped and the corresponding preset center coordinates in the X and Y directions at the shooting position, obtaining the cumulative deviation {ΔX... 推力装置 ΔY 推力装置}={ΔX1+ΔX2, ΔY1+ΔY2}, change {ΔX 推力装置 ΔY 推力装置 The compensation is added to the target movement coordinates of the thrust device.

[0097] (g) The angle between the straight line formed by the center point of the top circumferential feature of the thrust device after clamping and the center point of the No. 1 mounting hole of the thrust device itself and the X direction is denoted as λ1. The deviation of λ1 from the preset angle λ0 is denoted as Δλ. The angle between the straight line formed by the center point of the insertion hole of the thrust device base plate and the center point of the No. 1 mounting hole of the base plate and the X direction is denoted as δ1. The deviation of δ1 from the preset δ0 is denoted as Δδ. The cumulative deviation of the two sets of angles is used to obtain the program correction angle Δθ = Δδ + Δλ. The PLC drive component B assembly mechanism 3 compensates for the correction angle Δθ around the Z-axis.

[0098] (h) Through the calculations in steps (f) and (g), the top circumferential feature of the thrust device after clamping is aligned with the center of the insertion hole of the thrust device base plate, and the center of the No. 1 mounting hole of the thrust device itself is aligned with the center of the No. 1 mounting hole of the base plate. After calculation and compensation, the drive assembly mechanism 3 of component B moves the thrust device to the target assembly position.

[0099] (i) After the thrust device moves to the target assembly position and is assembled, the component B positioning and locking mechanism 4 locks and positions the thrust device. The component B assembly mechanism 3 releases the thrust device, and the horizontally gripping bolt reaches the shooting range of the component B position detection device 13. The component B position detection device 13 takes a picture of the bolt clamping state and calculates the deviation of the actual center coordinates of the bolt end face at the shooting position from the theoretical center coordinates in the X and Y directions {ΔX3, ΔY3}. At the same time, combined with the calculation in step (e), the deviation of the actual center from the theoretical center of the thrust device base plate 1# mounting hole {ΔX4, ΔY4} is obtained. The combined calculation yields {ΔX... 螺栓 ΔY 螺栓 =ΔX3+ΔX4,ΔY3+ΔY4}, compensate to the target bolt movement coordinates, after compensation move the bolt to the target mounting hole position and insert it into the bottom plate #1 mounting hole from below;

[0100] (j) Assembly mechanism 3 of component B maintains the clamping bolt state for back tightening when the nut is tightened. After the bolt is installed in place, the PLC drives the first four-axis collaborative robot 71 to horizontally clamp the shim from the axial material column 61. Combined with step (e), the deviation {ΔX4, ΔY4} between the actual center and the theoretical center of the mounting hole #1 on the base plate is calculated as {ΔX 垫片 ΔY 垫片 The compensation is applied to the target movement coordinates of the flat shim, and after compensation, the flat shim is moved above the target bolt and automatically fitted.

[0101] (k) The PLC drives the second four-axis collaborative robot 91 to reach the top of the base plate according to the predetermined program trajectory. The second vision positioning device 92 takes a picture of the position after the bolt is inserted, obtains the center coordinates of the top circumference of the bolt after assembly, and feeds the center coordinates back to the PLC.

[0102] (l) The PLC calculates the coordinate deviation {ΔX5, ΔY5} between the actual center of the top circumference of the bolt after assembly and the theoretical center of the bolt, obtained by the second vision positioning device 92, as {ΔX 螺母 ΔY 螺母 The coordinates are compensated to the target movement coordinates of the nut. After compensation, the nut is moved to the target installation position by the second four-axis collaborative robot 91 for pre-tightening.

[0103] (m) Replace the center coordinates of other mounting holes of the thrust device with the center coordinates of the corresponding bottom plate insertion holes, and repeat steps (h) to (l) to complete the pre-assembly of bolts, washers and nuts for mounting holes #2 and #3 of the bottom plate in sequence.

[0104] The present invention discloses an automatic assembly device for bolted connection structures. Through a vision inspection device, a control system, and coordinated operation among various components, it can replace the traditional manual assembly process of thrust devices, freeing up manpower and achieving automatic assembly of thrust devices. By adjusting the end structure of the clamping fixtures for components A and B, it can be flexibly applied to the assembly process of other components. Furthermore, by adjusting the structure of the flat washer clamping fixture, it can be quickly applied to the positioning and assembly process of components such as bolts and spring washers.

[0105] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solutions of the present invention by utilizing the methods and techniques disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the protection scope of the technical solutions of the present invention.

Claims

1. An automatic assembly device for components in a bolted connection structure, used to connect component B to component A via N sets of bolts, flat washers, and nuts; characterized in that, include: Component B assembly mechanism (3), Component B positioning and locking mechanism (4), bolt assembly mechanism (5), flat washer assembly mechanism (7), nut assembly mechanism (9), N>1; The component B positioning and locking mechanism (4) is provided with a locking part (41). The locking part (41) is provided with a second gripper (411) and N-1 guide positioning pins (413). The position of the guide positioning pins (413) corresponds to the mounting hole of component B. The guide positioning pins (413) can move telescopically along the Z-axis of the geodetic coordinate system. The second gripper (411) is used to grab and lock component B, and fix the X, Y, and Z degrees of freedom of component B in the geodetic coordinate system, as well as the rotational degree of freedom α around the X-axis and the rotational degree of freedom γ around the Y-axis. The N-1 guide positioning pins (413) are used to insert into the N-1 mounting holes of component B, and fix the rotational degree of freedom β of component B around the Z-axis. The component B assembly mechanism (3) is used to clamp component B and move it to the target installation position until the axes of the N mounting holes of component A and the N mounting holes of component B are all coincident; Bolt assembly mechanism (5) is used to clamp the bolt and move it to the mounting hole of component B without guide locating pin (413) and keep the bolt head in a tight position. The flat washer assembly mechanism (7) is used to clamp the flat washer and insert it into the bolt after the bolt is assembled; The nut assembly mechanism (9) is used to cooperate with the bolt assembly mechanism (5) after the flat washer is assembled. Under the back tightening action of the bolt assembly mechanism (5) on the bolt, the nut is tightened onto the external thread of the bolt. The component B assembly mechanism (3) includes a first collaborative robot (31) and a flexible fixture (32). The flexible fixture (32) is provided with a component B clamping part (321) and is assembled at the end of the first collaborative robot (31). At the connection point between the flexible fixture (32) and the first collaborative robot (31), a bolt clamping part (322) and a bolt back tightening part (323) are provided in a plane perpendicular to the component B clamping part (321). The bolt clamping part (322) and the bolt back tightening part (323) are respectively connected to the two ends of the component B clamping part (321) to integrate the functions of bolt clamping and back tightening on the component B assembly mechanism (3). When the flexible fixture (32) switches from the component B clamping part (321) to the bolt clamping part (322) to work, the component B assembly mechanism (3) is used as a bolt assembly mechanism (5).

2. The automatic assembly device for components in a bolted connection structure according to claim 1, characterized in that, The locking part (41) is also provided with a pen-shaped cylinder (414), which is connected to the guide positioning pin (413) and drives the guide positioning pin (413) to extend and retract along the Z-axis of the geodetic coordinate system. Before assembling the next bolt, the pen-shaped cylinder (414) drives the guide positioning pin (413) inserted in the corresponding mounting hole to lift up.

3. The automatic assembly device for components in a bolted connection structure according to claim 1, characterized in that, The component B clamping part (321) includes a gripper, a first cylinder (3211), and a pressure sensor (3212); The gripper is used to hold component B in motion. The first cylinder (3211) drives the gripper to open and close. The pressure sensor (3212) is located on the side wall of the gripper. When the gripper holds component B, the pressure sensor (3212) sends a pressure signal to confirm that component B is clamped.

4. The automatic assembly device for components in a bolted connection structure according to claim 1, characterized in that, The bolt clamping part (322) includes a bolt clamp (3223), a second cylinder (3221), and a spring (3222); The bolt clamp (3223) matches the bolt head, the second cylinder (3221) drives the bolt clamp (3223) to clamp, and the spring (3222) drives the bolt clamp (3223) to release; The bolt back tightening part (323) adopts a sleeve structure, and the end of the sleeve structure is provided with a cavity, the shape of which matches the bolt head.

5. An automatic assembly device for components in a bolted connection structure according to claim 4, characterized in that, The nut assembly mechanism (9) includes a third collaborative robot (91), and a tightening part (93) is fixed at the end of the third collaborative robot (91). Among them, the tightening part (93) adopts a combination assembly of tightening shaft and sleeve structure. The end of the tightening shaft is connected to the sleeve structure, and the sleeve structure is fitted on the nut for nut material removal. The tightening shaft has a torque sensor for tightening the nut according to the torque requirements.

6. The automatic assembly device for components in a bolted connection structure according to claim 5, characterized in that, The tightening of the nut onto the external thread of the bolt by the bolt assembly mechanism (5) under the back-tightening action of the bolt specifically includes: When assembling nuts, the nut pre-tightening operation is performed first. The tightening part (93) of the nut assembly mechanism (9) is used to tighten one end of the nut. At the same time, the bolt clamping part (322) is pressed against the bolt head for fixation. When the pre-tightening torque is reached, the tightening part (93) stops rotating and the next nut pre-tightening is performed. After all nuts are pre-tightened, the flexible fixture (32) switches the bolt back-tightening part (323) to work. The bolt back-tightening part (323) moves to the bolt installation position and presses against the bolt head. When the nut end is rotated to tighten, the bolt rotates accordingly. When the bolt head rotates to the position where the cavity of the bolt back-tightening part (323) can be inserted, the bolt back-tightening part (323) performs the back-tightening function. The tightening part (93) of the nut assembly mechanism (9) completes the formal tightening according to the rotation angle recorded when the pre-tightening is completed.

7. The automatic assembly device for components in a bolted connection structure according to claim 1, characterized in that, It also includes a flat gasket feeding mechanism (6), which includes an axial material column (61), a first pressing plate (62), a first locking nut (63), a first feeding cylinder (64), a first material feeding plate (65), a blow-off pipe (66), and a first slider (67). The first clamping plate (62) contacts the upper surface of the first slider (67), the first locking nut (63) is set on the upper surface of the first clamping plate (62) to apply a clamping force to the first clamping plate (62), the bottom of the axial column (61) is installed on the upper surface of the first slider (67), the first feeding plate (65) is set at the bottom of the axial column (61), the first feeding cylinder (64) is fixedly connected below the first feeding plate (65) to control the first feeding plate (65) to move and feed along the Z-axis of the geodetic coordinate system, the blow-out pipe (66) is set on one side of the axial column (61) with its blow-out end facing the end of the axial column (61); the flat gasket feeding mechanism (6) allows the flat gasket assembly mechanism (7) to take the flat gasket from the upper end of the axial column (61).

8. The automatic assembly device for components in a bolted connection structure according to claim 1, characterized in that: It also includes a nut feeding mechanism (8), which includes an axial material groove (81), a second pressure plate (82), a second locking nut (83), a second feeding cylinder (84), a second material feeding plate (85), and a second slider (86). The second clamping plate (82) contacts the upper surface of the second slider (86), the second locking nut (83) is set on the upper surface of the second clamping plate (82) to apply a clamping force to the second clamping plate (82), the bottom of the axial material groove (81) is installed on the upper surface of the second slider (86), the second feeding plate (85) is set at the bottom of the axial material groove (81), the second feeding cylinder (84) is fixed below the second feeding plate (85) to control the second feeding plate (85) to move the height of one nut along the axial direction each time; the nut feeding mechanism (8) allows the nut assembly mechanism (9) to take the nut from the upper end of the axial material groove (81).

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