Nuclear power pipeline variable-diameter cutting and grinding robot and cutting and grinding repair method thereof

Abstract

This invention provides a nuclear power pipeline diameter-changing cutting and grinding robot and its cutting and grinding repair method, relating to the field of pipeline grinding and repair technology. The cutting and grinding robot includes a drive component, a first support component, a cutting and grinding component, and a second support component. The drive component is connected to the first support component, and the cutting and grinding component is connected to the second support component via universal joints. In the drive component, the support plate is rotatably connected to the drive rod of the drive mechanism, and a screw nut is helically connected to the transmission screw. This invention drives the drive wheel to unfold through the transmission screw, the screw nut, and the linkage mechanism. In conjunction with the drive cylinder, the arc-shaped wheel and each elastic support wheel change diameter and fit against the pipe wall. The universal joints are connected in series to achieve differential speed bending of the pipe, ensuring the robot's passability and stability in straight pipes, diameter-changing pipes, and pipes with large curvature. The grinding wheel achieves composite grinding of revolution and rotation through the meshing of the central gear and planetary gears, realizing the integration of cutting, grinding, and chip collection, significantly improving grinding uniformity and repair efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of pipeline polishing repair, in particular to a nuclear power pipeline variable-diameter cutting and grinding robot and a cutting and grinding repair method thereof. BACKGROUND

[0002] The nuclear power main pipeline is the core pressure boundary of the nuclear reactor primary coolant system, and is the key channel connecting the reactor pressure vessel, the steam generator and the main pump. It needs to serve stably for a long time under the environment of high temperature, high pressure, high flow rate and strong neutron irradiation. The geometric precision and surface integrity of the inner wall directly determine the coolant flow field characteristics and deeply affect the stress corrosion resistance, fatigue and erosion corrosion resistance of the pipeline. During the manufacturing and in-service operation of the main pipeline, various typical surface defects inevitably occur on the inner wall: in the straight pipe section, due to the residual of forging or rolling process, local material yield, etc., unevenness in the form of hillocks will appear; in the elbow pipe section, the material on the inner side of the elbow pipe is easily unstable under the action of tangential compressive stress during medium-frequency heat bending or cold bending forming, and metal accumulation wrinkles are formed; and at the girth weld and the pipe connection weld of the pipeline, there are generally weld reinforcement, weld toe undercut and welding spatter, and welding slag residue. If the above defects are not repaired in time and accurately, the local flow resistance of the coolant will increase, the micro-eddy current and the turbulent flow will be intensified, which not only reduces the heat exchange efficiency, but also becomes a sensitive source of stress corrosion cracking, seriously threatening the structural integrity of the main pipeline and even the nuclear safety.

[0003] At present, the inner wall defect repair of nuclear power main pipeline is still mainly manual handheld polishing or simple rail trolley. However, the closed space with an inner diameter of only 500-900 mm seriously limits the movement of personnel, and the long-time high-vibration handheld operation is accompanied by metal dust, high noise and hot hazards, and the manual operation relies too much on experience, and it is difficult to accurately control the material removal amount, which is prone to local over-grinding to reduce the wall thickness beyond the limit or under-grinding residue, and it is difficult to meet the requirements of nuclear level size and surface integrity. The existing pipeline polishing device adopts a rigid whole body, and when facing a 90° sharp bend with a bending radius of only 1.5 times the pipe diameter, the wheel system is easy to be damaged, and the clamping and stagnation frequently occur, and the inner side wrinkle protrusion increases the passing difficulty, and it is difficult to maintain continuous and stable polishing posture. Functionally, the existing device only has single grinding capacity, and the direct polishing efficiency of millimeter-level protrusions such as straight pipe section hump and bend section wrinkle is extremely low, and the grinding tool is severely worn, and the instant dust collection function is not integrated; a large amount of metal cuttings and dust generated are easy to accumulate and scratch the repaired surface, and even remain as foreign matter in the primary loop system, which constitutes a fatal hidden danger of fuel element wear. In addition, the variable diameter mechanism is complex and has poor synchronicity, which causes uneven contact normal pressure of each group of supporting wheels, and the whole machine is easy to deviate, roll and vibrate during traveling under load, which seriously damages the polishing surface type accuracy and operation stability. It can be seen that the existing technology has fundamental deficiencies in narrow space adaptation, bend passing, grinding and dust collection integration, and pipe diameter flexible attachment, which has become a prominent problem restricting the inner wall defect repair of main pipeline. Therefore, it is necessary to propose a nuclear power pipeline variable diameter cutting and grinding robot and a cutting and grinding repair method thereof. SUMMARY

[0004] In order to solve the above-mentioned deficiencies of the prior art, the purpose of the present application is to provide a nuclear power pipeline variable diameter cutting and grinding robot and a cutting and grinding repair method thereof, which expands the driving wheel through a transmission screw, a screw nut and a connecting rod mechanism, cooperates with the driving cylinder to drive the arc wheel and each elastic supporting wheel to change the diameter and adhere to the pipe wall, realizes the differential bending of the bend through the universal joint in series, ensures the high passing performance and motion stability of the robot in the straight pipe, variable diameter and large curvature pipeline, realizes the composite grinding of the grinding wheel through the meshing of the center gear and the planetary gear, and guides and collects the waste by the closed dust collection space formed by the spiral guide ridge and the outer shell of the coaxial spiral dust collection groove, realizes the integration of cutting, grinding and dust collection, and significantly improves the grinding uniformity and repair efficiency.

[0005] This invention provides a nuclear power plant pipeline diameter-changing cutting and grinding robot, including a drive assembly, a first support assembly, a cutting and grinding assembly, and a second support assembly. The drive assembly is connected to the first support assembly, and the cutting and grinding assembly is connected to the second support assembly via universal joints. The drive assembly includes a support plate, a drive mechanism, a linkage mechanism, a transmission screw, and a screw motor. The support plate is rotatably connected to the first end of the drive rod in the drive mechanism. The fixed frame of the drive mechanism is rotatably connected to the first guide rod of the linkage mechanism. The second guide rod of the linkage mechanism is rotatably connected to a moving plate. A screw nut is screwed onto the transmission screw, and the screw nut is connected to the moving plate. The transmission screw is connected to the output shaft of the screw motor. The first support assembly includes a support mechanism, a drive cylinder, and an arc-shaped plate. The support mechanism is located at the first end of the main shaft in the cutting and grinding assembly. The cylinder seat of the drive cylinder is connected to the housing of the support mechanism, and the telescopic component of the drive cylinder is connected to... The system consists of an arc-shaped plate connection with an arc-shaped wheel on it; the cutting and grinding assembly includes a scraper holder, scraper, pressure plate, polishing brush, grinding wheel, fixed disk, central gear, and planetary gear. The scraper holder is sleeved on the second end of the main shaft, and the scraper is pressed onto the scraper holder by the pressure plate. The fixed disk is rotatably sleeved on the third end of the main shaft. The grinding wheel and planetary gear are coaxially fixed, and the fixed shaft of the planetary gear is slidably set in the groove of the fixed disk. The central gear is sleeved on the main shaft, and the planetary gear meshes with the central gear. The second support assembly includes a rotating component, a spring rod, a support rod, and a tube support mechanism. The rotating component is sleeved on the fourth end of the main shaft. The first end of the spring rod is connected to the rotating component. A third spring is provided between the second end of the spring rod and the first end of the support rod. The support rod is connected to the connecting sleeve of the tube support mechanism, and the connecting sleeve is rotatably connected to the guide plate of the tube support mechanism. Wheel mechanisms are provided at both ends of the guide plate.

[0006] Preferably, the drive mechanism includes a drive wheel, a drive motor, a first bevel gear, and a second bevel gear. The output shaft of the drive motor is connected to the second bevel gear. The axes of the first bevel gear and the second bevel gear are perpendicular and mesh with each other. The drive wheel is coaxially connected to the first bevel gear, and both ends of the drive wheel are rotatably connected to the second end of the drive rod. The fixed frame is located in the middle of the drive rod, and the drive motor is mounted on the fixed frame.

[0007] Preferably, the linkage mechanism includes a first guide rod, a first spring, a sliding rod, and a second guide rod. A spring sleeve is provided on the first guide rod, and the two ends of the first spring are respectively connected to the second guide rod and the spring sleeve. The first end of the sliding rod is connected to the second guide rod, and the second end of the sliding rod is slidably disposed in the first guide rod.

[0008] Preferably, the housing and end cap of the support mechanism are sequentially fitted onto the support shaft, the arc-shaped wheel is arranged in a zigzag pattern along the axial direction, and multiple nozzles are arranged circumferentially at one end of the support shaft near the cutting and grinding assembly.

[0009] Preferably, the polishing brush, the central gear, and the spiral chip collection groove are all coaxially arranged, the grinding wheel is set in the groove of the fixed plate, and a second spring is provided between the scraper and the scraper seat.

[0010] Preferably, the center gear and planetary gear are provided with an outer shell, and the outer shell and the spiral chip collecting groove form a chip collecting space, and the groove wall of the spiral chip collecting groove is provided with a spiral guide ridge.

[0011] Preferably, the wheel mechanism includes a wheel and an axle, with the wheel rotatably connected to the guide plate of the tube support mechanism via the axle.

[0012] Secondly, the present invention also provides a method for cutting and grinding repair of nuclear power plant pipelines using a variable diameter cutting and grinding robot, the steps of which include: S1. The cutting and grinding robot is placed inside the pipe. The lead screw motor drives the transmission lead screw through the lead screw nut and connecting rod mechanism, which drives the drive mechanism to unfold synchronously until the drive wheel contacts the pipe wall. The drive cylinder and the third spring are adjusted to make the arc wheel and the wheel mechanism fit against the inner wall of the pipe.

[0013] S2. The drive motor drives the drive wheel to rotate via the bevel gear pair, driving the cutting and grinding robot to the repair area. The speed of each drive motor is adjusted according to the curvature of the pipe to control the differential speed of the cutting and grinding robot to pass through the bend.

[0014] S3. The spindle motor drives the spindle to rotate the cutting and grinding assembly. At the same time, the nozzle blows the tube wall, the scraper cuts the defects under the action of the second spring, and polishes the tube with the polishing brush. The grinding wheel revolves with the spindle and rotates through the meshing of the central gear and the planetary gear to perform compound grinding.

[0015] S4. The cutting chips are guided by the spiral guide ridge of the spiral chip collection groove to the chip collection space formed by the outer shell. After completing the current area to be repaired, the cutting and grinding robot moves along the axis to the next area to be repaired.

[0016] S5. Repeat steps S3 to S4 until the defect repair operation is completed. The cutting and grinding robot exits the pipeline, and the lead screw motor drives the lead screw in the reverse direction to make the drive mechanism retract and detach from the pipe wall.

[0017] Preferably, in step S2, differential cornering is achieved by using universal joints connected in series among the components to allow the cutting and grinding robot to adaptively deflect the pipe curvature. Based on the curvature radius of the inner and outer sides of the bend, the speed of each drive motor is adjusted so that the speed of the outer wheel is greater than that of the inner wheel, thus enabling the cutting and grinding robot to corner at differential speed.

[0018] Preferably, in step S3, the relationship between the external dimension L of the cutting and grinding robot and the geometric parameters of the pipe is as follows: ; In the formula, w is the width of the robot, R is the radius of curvature of the bend, D is the inner diameter of the pipe, and λ0 is the bending angle of the bend.

[0019] Compared with the prior art, the beneficial effects of the present invention are reflected in: (1) The nuclear power pipeline diameter changing cutting and grinding robot of the present invention drives the transmission screw and screw nut through the screw motor, drives the linkage mechanism to make the drive wheel unfold synchronously, and cooperates with the drive cylinder in the first support component to push the arc-shaped wheel, so that each support wheel can change diameter and fit the pipe wall. Through the flexible connection of the universal joints connected in series between each section component, the robot can adapt to the curvature of the pipeline and realize the differential speed of the inner and outer wheels to bend at the bend, so as to achieve high passability and motion stability of the robot in the complex nuclear power main pipeline with straight pipe, diameter changing and large curvature bend.

[0020] (2) The nuclear power pipeline variable diameter cutting and grinding robot of the present invention uses a second spring between the scraper and the scraper seat of the cutting and grinding component to enable the scraper to extend and retract radially to buffer, adapt to the pipe wall and avoid rigid collision. The grinding wheel is driven to rotate on its own axis while revolving around the main shaft through the meshing of the central gear and the planetary gear on the main shaft to achieve composite grinding. The waste chips are guided and collected by the spiral chip collection groove set coaxially with the main shaft, using the spiral guide ridge on the groove wall and the closed chip collection space formed by the outer shell. The cutting, grinding and chip collection are highly integrated, which significantly improves the grinding uniformity and repair efficiency. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the overall structure of the nuclear power pipeline diameter-changing cutting and grinding robot of the present invention; Figure 2 This is a front view schematic diagram of the nuclear power pipeline diameter-changing cutting and grinding robot of the present invention; Figure 3 This is an overall AA sectional view of the nuclear power plant pipeline diameter-changing cutting and grinding robot of the present invention; Figure 4 This is a schematic diagram of the drive components in the nuclear power pipeline diameter-changing cutting and grinding robot of the present invention; Figure 5 This is a schematic diagram of the drive mechanism of the drive component in the nuclear power pipeline variable diameter cutting and grinding robot of the present invention; Figure 6 This is a top view of the first support component in the nuclear power pipeline diameter-changing cutting and grinding robot of the present invention; Figure 7 This is a cross-sectional view of the first support component AA in the nuclear power pipeline diameter-changing cutting and grinding robot of the present invention; Figure 8 This is a cross-sectional view (AA) of the cutting and grinding component in the nuclear power pipeline diameter-changing cutting and grinding robot of the present invention; Figure 9 This is a cross-sectional view of the cutting and grinding component BB in the nuclear power pipeline diameter-changing cutting and grinding robot of the present invention; Figure 10 This is a structural diagram of the cutting and grinding components of the nuclear power pipeline variable diameter cutting and grinding robot of the present invention; Figure 11 This is a structural diagram of the second support component in the nuclear power pipeline variable diameter cutting and grinding robot of the present invention; Figure 12 This is a cross-sectional view of the second support component AA in the nuclear power pipeline diameter-changing cutting and grinding robot of the present invention; Figure 13 This is a schematic diagram of the nuclear power pipeline diameter-changing cutting and grinding robot of the present invention working in a straight pipe; Figure 14 This is a schematic diagram of the nuclear power pipeline diameter-changing cutting and grinding robot of the present invention working in a bend.

[0022] Figure label: Drive assembly 100, support plate 101, drive mechanism 102, drive rod 1021, drive motor 1022, fixed frame 1023, first bevel gear 1024, second bevel gear 1025, drive wheel 1026, linkage mechanism 104, first guide rod 1041, first spring 1042, sliding rod 1043, second guide rod 1044, transmission screw 105, screw nut 106, screw motor 107, universal joint 114, first support assembly 200, support machine The components include: 201, drive cylinder 202, arc plate 203, nozzle 204, support shaft 205, chip collection groove 206, cutting and grinding assembly 300, polishing brush 301, grinding wheel 302, fixed plate 303, main shaft 307, scraper 309, central gear 310, planetary gear 311, pressure plate 314, second support assembly 400, rotating part 401, tube support mechanism 402, wheel mechanism 404, rotating shaft 4041, wheel 4042, support rod 405, and spring rod 406. Detailed Implementation

[0023] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0024] This invention provides a nuclear power plant pipeline diameter-changing cutting and grinding robot, such as... Figures 1-3 As shown, the assembly includes a drive component 100, a first support component 200, a cutting and grinding component 300, and a second support component 400. The drive component 100 is connected to the first support component 200, and the cutting and grinding component 300 is connected to the second support component 400 via universal joints 114. During the repair operation, the second support component 400 fits against the inner wall of the pipe to provide auxiliary support for the cutting and grinding component 300, which can effectively suppress vibration and sway caused by the cantilever structure and improve the cutting and grinding accuracy.

[0025] like Figure 4 and Figure 5As shown, the drive assembly 100 includes a support plate 101, a drive mechanism 102, a linkage mechanism 104, a transmission screw 105, and a screw motor 107. The support plate 101 is rotatably connected to the first end of the drive rod 1021 in the drive mechanism 102. The fixed frame 1023 of the drive mechanism 102 is rotatably connected to the first guide rod 1041 of the linkage mechanism 104. The second guide rod 1044 of the linkage mechanism 104 is rotatably connected to the moving plate 107. A screw nut 106 is screwed onto the transmission screw 105. The screw nut 106 is connected to the moving plate 107. The transmission screw 105 is connected to the output shaft of the screw motor 107. The drive mechanism 102 includes a drive wheel 1026, a drive motor 1022, a first bevel gear 1024, and a second bevel gear 1025. The output shaft of the drive motor 1022 is connected to the second bevel gear 1025. The axes of the first bevel gear 1024 and the second bevel gear 1025 are perpendicular and meshed. The drive wheel 1026 is coaxially connected to the first bevel gear 1024, and both ends of the drive wheel 1026 are rotatably connected to the second end of the drive rod 1021. A fixed frame 1023 is disposed in the middle of the drive rod 1021, and the drive motor 1022 is disposed on the fixed frame 1023. The connecting rod... Mechanism 104 includes a first guide rod 1041, a first spring 1042, a sliding rod 1043, and a second guide rod 1044. A spring sleeve is provided on the first guide rod 1041. The two ends of the first spring 1042 are respectively connected to the second guide rod 1044 and the spring sleeve. The first end of the sliding rod 1043 is connected to the second guide rod 1044, and the second end of the sliding rod 1043 is slidably disposed in the first guide rod 1041. Through the linkage mechanism 104, the three sets of drive mechanisms 102 are driven to expand or retract synchronously, thereby realizing the adaptive adjustment of pipes with different diameters and ensuring that the force on each set of wheels is uniform.

[0026] like Figure 6 and Figure 7 As shown, the first support assembly 200 includes a support mechanism 201, a drive cylinder 202, and an arc plate 203. The support mechanism 201 is disposed at the first end of the main shaft 307 in the cutting and grinding assembly 300. The cylinder seat of the drive cylinder 202 is connected to the housing of the support mechanism 201. The telescopic component of the drive cylinder 202 is connected to the arc plate 203. An arc wheel is provided on the arc plate 203. The housing and end cap of the support mechanism 201 are sequentially sleeved on the support shaft 205. The arc wheel is arranged in a zigzag pattern along the axial direction. A plurality of nozzles 204 are arranged circumferentially at one end of the support shaft 205 near the cutting and grinding assembly 300.

[0027] like Figures 8-10As shown, the cutting and grinding assembly 300 includes a scraper holder, a scraper 309, a pressure plate 314, a polishing brush 301, a grinding wheel 302, a fixed disc 303, a central gear 310, and a planetary gear 311. The scraper holder is sleeved on the second end of the main shaft 307. The scraper 309 is pressed onto the scraper holder by the pressure plate 314, allowing the scraper 309 to compress the spring backward when subjected to excessive radial force, avoiding rigid collision with the inner wall of the pipe, thereby extending the tool life. It can also adapt to pipes of different diameters. The fixed disc 303 is rotatably sleeved on the main shaft. At the third end of 307, the grinding wheel 302 is coaxially fixed with the planetary gear 311. The fixed shaft of the planetary gear 311 is slidably disposed in the groove of the fixed disk 303. The central gear 310 is sleeved on the main shaft 307, and the planetary gear 311 meshes with the central gear 310. The polishing brush 301, the central gear 310, and the spiral chip collection groove 206 are all coaxially disposed on the main shaft 307. The grinding wheel 302 is disposed in the groove of the fixed disk 303 by means of a fixing member and a washer. A second spring is disposed between the scraper 309 and the scraper seat. The gears 310 and 311 are externally equipped with housings, which together with the helical chip collection groove 206 form a chip collection space. The helical chip collection groove 206 has helical guide ridges on its groove walls. The grinding wheel 302 is locked and fixed to the fixed disk 303 by a grinding wheel fixing nut and a washer. The fixed disk 303 has multiple radially extending mounting grooves evenly distributed circumferentially. The grinding wheel 302 achieves graded adjustment of the radial grinding amount by selecting different mounting groove positions. The fixed disk 303 is rotatably mounted on the spindle 307 via a deep groove ball bearing. The central gear 3... 10 is coaxially connected to the supporting spindle 307, and the planetary gear 311 is coaxially connected to the fixed disk 303. The central gear 310 and the planetary gear 311 mesh externally to form a fixed-axis planetary gear system. When the spindle 307 is driven to rotate by the spindle motor, the central gear 310 revolves synchronously with the spindle 307 and drives the planetary gear 311 to drive the fixed disk 303 and the grinding wheel 302 to rotate in the opposite direction around its own axis. The speed ratio of revolution and rotation is determined by the tooth ratio of the central gear 310 and the planetary gear 311, forming a compound grinding motion on the tube wall.

[0028] like Figure 11 and Figure 12 As shown, the second support assembly 400 includes a rotating member 401, a spring rod 406, a support rod 405, and a tube support mechanism 402. The rotating member 401 is sleeved on the fourth end of the main shaft 307. The first end of the spring rod 406 is connected to the rotating member 401. A third spring is provided between the second end of the spring rod 406 and the first end of the support rod 405. The support rod 405 is connected to the connecting sleeve of the tube support mechanism 402. The connecting sleeve is rotatably connected to the guide plate of the tube support mechanism 402. Wheel mechanisms 404 are provided at both ends of the guide plate. The wheel mechanism 404 includes a wheel 4042 and a rotating shaft 4041. The wheel 4042 is rotatably connected to the guide plate of the tube support mechanism 402 through the rotating shaft 4041.

[0029] On the other hand, such as Figure 13 and Figure 14 As shown, this invention provides a cutting and grinding repair method for a nuclear power plant pipeline reducing diameter cutting and grinding robot, the steps of which include: S1. The cutting and grinding robot is placed inside the pipe. The lead screw motor 107 drives the transmission lead screw 105 through the lead screw nut 106 and the linkage mechanism 104, which drives the drive mechanism 102 to unfold synchronously until the drive wheel 1026 contacts the pipe wall. The drive cylinder 202 and the third spring are adjusted to make the arc wheel and the wheel mechanism 404 fit against the inner wall of the pipe.

[0030] S2. Drive the drive wheel 1026 to rotate via the drive motor 1022 through the bevel gear pair, and drive the cutting and grinding robot to the repair area. Adjust the speed of each drive motor 1022 according to the curvature of the pipe to control the differential speed of the cutting and grinding robot to pass through the bend.

[0031] The cutting and grinding robot can turn corners at differential speed by using universal joints 114 connected in series with each component to make the angle of the cutting and grinding robot adaptively deflect the curvature of the pipe. According to the curvature radius of the inner and outer sides of the bend, the speed of each drive motor 1022 is adjusted so that the speed of the outer wheel is greater than that of the inner wheel, thus enabling the cutting and grinding robot to turn corners at differential speed.

[0032] S3. The spindle motor drives the spindle 307 to rotate the cutting and grinding assembly 300. At the same time, the nozzle 204 blows the tube wall, the scraper 309 cuts the defects under the action of the second spring, and polishes them with the polishing brush 301. The grinding wheel 302 revolves with the spindle 307 and rotates through the meshing of the central gear 310 and the planetary gear 311 to perform compound grinding.

[0033] The relationship between the external dimension L of the cutting and grinding robot and the geometric parameters of the pipe is as follows: ; In the formula, w is the width of the robot, R is the radius of curvature of the bend, D is the inner diameter of the pipe, and λ0 is the bending angle of the bend.

[0034] The relationship between the width w of the cutting and grinding robot and the pipe geometry parameters: ; To ensure the cutting and grinding robot does not get stuck at the bend in the pipe, its maximum length can be obtained from geometric relationships: ; The cutting and grinding robot navigates a bend in a pipe with a minimum radius of curvature of 1.5 times the pipe's inner diameter and a minimum angle of 90°, under the following conditions: ; Length range of cutting and grinding robots: ; Second condition: ; Length range of cutting and grinding robots: .

[0035] S4. The cutting chips are guided by the spiral guide ridge of the spiral chip collection groove 206 to the chip collection space formed by the outer shell. After completing the current area to be repaired, the cutting and grinding robot moves along the axis to the next area to be repaired.

[0036] S5. Repeat S3 to S4 until the defect repair operation is completed. The cutting and grinding robot exits the pipeline, and the lead screw motor 107 drives the lead screw 105 in the reverse direction to make the drive mechanism 102 retract and detach from the pipe wall.

[0037] The nuclear power pipeline diameter-changing cutting and grinding robot and its cutting and grinding repair method provided by this invention drive the drive wheel 1026 synchronously through the transmission screw 105 via the screw nut 106 and the linkage mechanism 104. The drive cylinder 202 drives the arc wheel and each elastic support wheel to change diameter and fit against the pipe wall. The universal joint 114 is connected in series to realize the differential speed of the bend, ensuring the robot's high passability and motion stability in straight pipes, diameter-changing pipes and pipes with large curvature. The cutting and grinding assembly 300 has a second spring between the scraper 309 and the tool holder, which gives the scraper 309 radial extension and buffering ability to avoid rigid collisions. The grinding wheel 302 achieves compound grinding of revolution and rotation by the meshing of the central gear 310 and the planetary gear 311. The coaxial spiral chip collection groove 206 forms a closed chip collection space with the outer shell through the spiral guide ridge, guiding and collecting waste chips, realizing the integration of cutting, grinding and chip collection, significantly improving grinding uniformity and repair efficiency.

[0038] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A nuclear power plant pipeline diameter-changing cutting and grinding robot, characterized in that, It includes a drive assembly, a first support assembly, a cutting and grinding assembly, and a second support assembly. The drive assembly is connected to the first support assembly, and the cutting and grinding assembly is connected to the second support assembly via universal joints. The drive assembly includes a support plate, a drive mechanism, a linkage mechanism, a transmission screw, and a screw motor. The support plate is rotatably connected to the first end of the drive rod in the drive mechanism. The fixed frame of the drive mechanism is rotatably connected to the first guide rod of the linkage mechanism. The second guide rod of the linkage mechanism is rotatably connected to the moving plate. A screw nut is screwed onto the transmission screw, and the screw nut is connected to the moving plate. The transmission screw is connected to the output shaft of the screw motor. The first support assembly includes a support mechanism, a drive cylinder, and an arc plate. The support mechanism is located at the first end of the spindle in the cutting and grinding assembly. The cylinder seat of the drive cylinder is connected to the housing of the support mechanism. The telescopic component of the drive cylinder is connected to the arc plate. An arc wheel is provided on the arc plate. The cutting and grinding assembly includes a scraper holder, a scraper, a pressure plate, a polishing brush, a grinding wheel, a fixed disc, a central gear, and a planetary gear. The scraper holder is sleeved on the second end of the main shaft, and the scraper is pressed onto the scraper holder by the pressure plate. The fixed disc is rotatably sleeved on the third end of the main shaft. The grinding wheel and the planetary gear are coaxially fixed. The fixed shaft of the planetary gear is slidably set in the groove of the fixed disc. The central gear is sleeved on the main shaft, and the planetary gear meshes with the central gear. The second support assembly includes a rotating component, a spring rod, a support rod, and a tube support mechanism. The rotating component is sleeved on the fourth end of the main shaft. The first end of the spring rod is connected to the rotating component. A third spring is provided between the second end of the spring rod and the first end of the support rod. The support rod is connected to the connecting sleeve of the tube support mechanism. The connecting sleeve is rotatably connected to the guide plate of the tube support mechanism. Wheel mechanisms are provided at both ends of the guide plate.

2. The nuclear power plant pipeline diameter changing and grinding robot according to claim 1, characterized in that, The drive mechanism includes a drive wheel, a drive motor, a first bevel gear, and a second bevel gear. The output shaft of the drive motor is connected to the second bevel gear. The axes of the first bevel gear and the second bevel gear are perpendicular and mesh with each other. The drive wheel is coaxially connected to the first bevel gear, and both ends of the drive wheel are rotatably connected to the second end of the drive rod. The fixed frame is set in the middle of the drive rod, and the drive motor is set on the fixed frame.

3. The nuclear power plant pipeline diameter-changing cutting and grinding robot according to claim 1, characterized in that, The linkage mechanism includes a first guide rod, a first spring, a sliding rod, and a second guide rod. A spring sleeve is provided on the first guide rod. The two ends of the first spring are respectively connected to the second guide rod and the spring sleeve. The first end of the sliding rod is connected to the second guide rod, and the second end of the sliding rod is slidably disposed in the first guide rod.

4. The nuclear power plant pipeline diameter-changing cutting and grinding robot according to claim 1, characterized in that, The housing and end cap of the support mechanism are sequentially fitted onto the support shaft. The arc-shaped wheel is arranged in a zigzag pattern along the axial direction. Multiple nozzles are arranged circumferentially at one end of the support shaft near the cutting and grinding assembly.

5. The nuclear power plant pipeline diameter-changing cutting and grinding robot according to claim 1, characterized in that, The polishing brush, central gear, and spiral chip collection groove are all coaxially arranged. The grinding wheel is set in the groove of the fixed plate, and a second spring is provided between the scraper and the scraper seat.

6. The nuclear power plant pipeline diameter-changing cutting and grinding robot according to claim 1, characterized in that, The center gear and planetary gear are equipped with outer shells. The outer shells and the spiral chip collection groove form a chip collection space. The spiral chip collection groove has spiral guide ridges on its groove wall.

7. The nuclear power plant pipeline diameter-changing cutting and grinding robot according to claim 1, characterized in that, The wheel mechanism includes a wheel and an axle. The wheel is rotatably connected to the guide plate of the tube support mechanism via the axle.

8. A method for cutting and grinding repair of nuclear power plant pipelines using a variable diameter cutting and grinding robot as described in any one of claims 1 to 7, characterized in that, The steps include: S1. The cutting and grinding robot is placed inside the pipe. The lead screw motor drives the transmission lead screw through the lead screw nut and the linkage mechanism, which drives the drive mechanism to unfold synchronously until the drive wheel contacts the pipe wall. The drive cylinder and the third spring are adjusted to make the arc wheel and the wheel mechanism fit against the inner wall of the pipe. S2. The drive motor drives the drive wheel to rotate through the bevel gear pair, driving the cutting and grinding robot to the repair area. The speed of each drive motor is adjusted according to the curvature of the pipe to control the differential speed of the cutting and grinding robot to pass through the bend. S3. The spindle motor drives the spindle to rotate the cutting and grinding assembly. At the same time, the nozzle blows the tube wall, the scraper cuts the defects under the action of the second spring, and polishes them with the polishing brush. The grinding wheel revolves with the spindle and rotates by meshing with the central gear and planetary gear to perform compound grinding. S4. The cutting chips are guided by the spiral guide ridge of the spiral chip collection groove to the chip collection space formed by the outer shell. After completing the current area to be repaired, the cutting and grinding robot moves along the axis to the next area to be repaired. S5. Repeat steps S3 to S4 until the defect repair operation is completed. The cutting and grinding robot exits the pipeline, and the lead screw motor drives the lead screw in the reverse direction to make the drive mechanism retract and detach from the pipe wall.

9. The cutting and grinding repair method of the nuclear power plant pipeline reducing diameter cutting and grinding robot according to claim 8, characterized in that, The specific control of differential cornering in step S2 is as follows: through the universal joints connected in series of each component, the angle of the cutting and grinding robot is adaptively deflected to the curvature of the pipe. According to the curvature radius of the inner and outer sides of the bend, the speed of each drive motor is adjusted so that the speed of the outer wheel is greater than that of the inner wheel, thus completing the differential cornering of the cutting and grinding robot.

10. The cutting and grinding repair method of the nuclear power pipeline reducing cutting and grinding robot according to claim 8, characterized in that, In step S3, the relationship between the external dimension L of the cutting and grinding robot and the geometric parameters of the pipe is as follows: ； In the formula, w is the width of the robot, R is the radius of curvature of the bend, D is the inner diameter of the pipe, and λ0 is the bending angle of the bend.

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