Device and method for machining threaded hole in steam generator

Abstract

The invention discloses a device and method for machining a threaded hole in a steam generator, the device is a large rotary device placed in a cylinder, the rotary positioning and repeated positioning precision meets the product drawing design requirement, and a specific machining device used for machining threads is installed on a rotary arm of the device. The machining equipment can move to a to-be-machined position along with the rotating arm; the levelness and coaxiality of the main shaft on the machining equipment and the to-be-machined device are adjusted at the same time to ensure that the machined threaded hole meets the design requirement.

Description

Technical Field

[0001] The invention relates to the field of auxiliary machinery used in the manufacture of nuclear power equipment, and in particular to a device and method for machining threaded holes inside a steam generator. Background Art

[0004] In 2021, the world's first high-temperature gas-cooled reactor nuclear power plant demonstration project (HTR-PM) with nuclear power operation was put into operation. The 36-M64X3 threaded holes on the main helium fan support flange and the 36-M42X2 threaded holes on the shell cylinder internal component support flange were all processed before welding with the upper cylinder and the main flange of the cylinder. There are no problems such as narrow processing space. However, after the overall heat treatment of the shell cylinder assembly, the assembly will be deformed, which will directly affect the tolerance accuracy of the threaded holes, such as position, verticality, roughness, etc., and bring serious difficulties to the subsequent assembly of the whole machine.

[0005] The main helium fan support flange of the steam generator of the 600MW high-temperature gas-cooled reactor nuclear power plant is welded with the straight section of the fan shell cylinder and the lower flange of the fan shell cylinder, and then the steam generator shell cylinder assembly is heat treated as a whole. Then, it is necessary to face the technical difficulty of processing 36-M64X3 threaded holes on the main helium fan support flange inside the cylinder. Correspondingly, after the internal component support flange of the steam generator shell cylinder is welded with the upper cylinder and the main flange of the cylinder, the steam generator shell cylinder assembly is heat treated as a whole. Then, it is necessary to face the technical difficulty of processing 36-M42X2 threaded holes on the internal component support flange of the cylinder.

[0006] The overall height of the fan casing assembly is nearly 4699mm, and the span of the threaded holes to be processed The pitch circle of the threaded hole is 110mm from the inner wall of the cylinder. The overall height of the steam generator shell cylinder assembly is nearly 7500mm, and the span of the threaded hole to be processed is The pitch circle of the threaded hole is 60mm from the inner wall of the cylinder. The threaded hole is processed on such a large structural component with a narrow space and position. At present, the existing large-scale machining equipment (such as large boring machines, gantry milling machines) cannot complete it. The main helium fan support flange also needs to ensure that the hole accuracy reaches the verticality: 0.2mm, the position accuracy: Thread roughness: Ra3.2μm. The hole accuracy on the supporting flange of the internal component of the steam generator shell cylinder needs to be guaranteed to reach the verticality: Position degree: Thread roughness: Ra3.2μm.

[0007] In summary, based on the above-mentioned specific and complex technical problems, the inventors have conducted in-depth research on threaded hole processing equipment, in the hope of designing a device and method for milling threaded holes on the supporting flange of the main helium fan of the steam generator that can solve the above-mentioned problems. The device and method are used to complete the milling processing task of the 36-M64X3 threaded holes on the supporting flange of the main helium fan of the steam generator. A device and method for drilling / tapping threads inside the steam generator cylinder are also provided. The device and method are used to complete the processing task of the 36-M42X2 threaded holes on the supporting flange of the internal component of the steam generator shell cylinder, and both can ensure that the quality of the threaded holes meets the quality requirements of nuclear power equipment. Summary of the invention

[0008] In order to overcome the above-mentioned problems, the inventors have conducted intensive research and designed a device and method for processing threaded holes inside a steam generator. The device is a large-scale rotary equipment placed inside the cylinder. The rotary positioning and repeat positioning accuracy meet the design requirements of the product drawings. A specific processing equipment for processing threads is installed on the rotating arm of the equipment. The processing equipment can be moved to the processing position with the rotating arm. The horizontality and coaxiality of the main shaft on the processing equipment and the device to be processed are simultaneously adjusted to ensure that the threaded hole obtained by processing meets the design requirements; thus completing the present invention.

[0009] Specifically, the object of the present invention is to provide a device for processing threaded holes inside a steam generator, the device comprising a turntable mounting bracket 1 and a turntable base 2, 8 adjustable shims 11 are arranged on the turntable mounting bracket 1, and the 8 adjustable shims 2 are evenly distributed in a ring shape on the top surface of the turntable mounting bracket 1;

[0010] The rotating table base 2 is installed on the adjustable shim 11, and the horizontality of the rotating table base 2 can be adjusted by the adjustable shim 11;

[0011] On the turntable mounting bracket 1, 8 centering screws 12 are evenly arranged around the turntable base 2, and the coaxiality of the rotation center of the turntable base 2 and the rotation center of the main helium blower support flange is adjusted by the centering screws 12;

[0012] A rotatable rotating table 3 is arranged in the middle of the rotating table base 2, and a rotating arm 31 and a counterweight arm 32 that rotate together are arranged on the rotating table 3, and a three-axis linkage CNC thread milling machine 4 is arranged on the rotating arm 31; the spindle of the three-axis linkage CNC thread milling machine 4 is transported to the top of the threaded hole to be milled on the supporting flange of the main helium fan through the rotating table 3 and the rotating arm 31, and the threaded hole is milled on the supporting flange of the main helium fan by the three-axis linkage CNC thread milling machine 4.

[0013] The three-axis CNC thread milling machine 4 includes a spindle 41, a Y-axis driving assembly 42 for controlling the spindle 41 to move along the Y-axis direction, an X-axis driving assembly 43 for controlling the spindle 41 to move along the X-axis direction, a Z-axis driving assembly 44 for controlling the spindle 41 to move along the Z-axis direction, and a spindle driving assembly 45 for driving the spindle 41 to rotate;

[0014] The Y-axis direction is the radial direction of the rotating table 3 , the Z-axis direction is the axial direction of the rotating table 3 , and the Y-axis direction is perpendicular to the X-axis direction and the Z-axis direction.

[0015] Wherein, above the rotating table base 2, a positioning and fixing bracket 21 is provided on the side of the rotating arm 31, and the positioning and fixing bracket 21 can slide on the rotating table base 2 as the rotating arm 31 rotates;

[0016] A number of n holes 22 are evenly distributed in a ring shape on the rotating table base 2, a through hole 211 is provided on the positioning and fixing bracket 21, and a cylindrical pin passes through the through hole 211 and the hole 22 to connect and position the rotating arm 31 and the rotating table base 2, thereby improving the stability of the three-axis linkage CNC thread milling machine 4 during milling processing; n is the number of holes to be processed on the cylinder to be processed.

[0017] Among them, a swivel arm support assembly is also arranged between the swivel arm 31 and the turntable base 2, and the swivel arm support assembly can slide on the turntable base 2 as the swivel arm 31 rotates. When the three-axis linkage CNC thread milling machine 4 is working, the swivel arm support assembly provides vertical upward support force for the swivel arm 31.

[0018] Wherein, the swing arm support assembly includes a bull's eye bearing 33 and an auxiliary support rod 34;

[0019] The auxiliary support rod 34 is vertically arranged, one end of which is fixed to the rotating arm 31, and the other end is fixed to the bull's eye bearing 33, and abuts against the rotating table base 2 through the bull's eye bearing 33;

[0020] Preferably, an annular groove 23 is provided on the rotating table base 2, and the bull's eye bearing 33 is embedded in the annular groove 23 and then slides along the annular groove 23;

[0021] Preferably, the vertical height of the auxiliary support rod 34 is adjustable.

[0022] Wherein, a dividing encoder is arranged on the rotating table 3, and the dividing encoder is used to control the rotating table 3 to rotate at an angle of 360n degrees each time.

[0023] The present invention also provides a method for machining threaded holes inside a steam generator, wherein the method comprises milling threaded holes on a supporting flange of a main helium blower of the steam generator, and the method is implemented by the device for machining threaded holes inside a steam generator as described above.

[0024] The method comprises the following steps:

[0025] Step 1: The main helium fan support flange of the steam generator is welded to the straight section of the fan casing cylinder and the lower flange of the fan casing cylinder. After overall heat treatment, the main helium fan support flange is aligned and marked, the center positions of n threaded holes to be processed are determined and marked, and then the welded steam generator cylinder is hoisted onto a cast iron platform with a T-slot;

[0026] Step 2, assembling the device for milling threaded holes on the supporting flange of the main helium blower of the steam generator on the outside of the steam generator cylinder;

[0027] Step 3, hoisting the assembled device for milling threaded holes on the main helium fan support flange of the steam generator into the interior of the steam generator cylinder, adjusting the coaxiality and parallelism between the device body and the main helium fan support flange, and fixing them;

[0028] Step 4, aligning the center of the main axis of the three-axis linkage CNC thread milling machine 4 on the device with the center of any threaded hole to be milled; the threaded hole to be milled is the first hole;

[0029] Step 5, connect the rotating arm 31 and the rotating table base 2 by passing a cylindrical pin through the through hole 211 and the hole 22; eliminate the deflection on the rotating arm 31 by adjusting the vertical height of the auxiliary support rod 34;

[0030] Step 6, milling the first threaded hole by a three-axis CNC thread milling machine 4;

[0031] Step 7, take out the cylindrical pin, control the rotating table 3 to rotate 360n degrees, and then insert the cylindrical pin;

[0032] Step 8, milling the second threaded hole by the three-axis CNC thread milling machine 4;

[0033] Step 9, repeat steps 7 and 8 until the milling of all n threaded holes is completed.

[0034] Among them, in step 2, the following sub-steps are specifically included: install the turntable base 2 and the turntable plate 3 thereon onto the adjustable shim 11 of the turntable mounting bracket 1, then install the three-axis linkage CNC thread milling machine 4 onto the turntable arm 31, and install the electrical cabinet of the electrical control system on the counterweight arm 32.

[0035] Among them, in step 4, a center is installed on the spindle of the three-axis linkage CNC thread milling machine 4, and the alignment is achieved by rotating the rotating table 3 and controlling the spindle of the three-axis linkage CNC thread milling machine 4 to slide along the Y-axis direction.

[0036] The beneficial effects of the present invention include:

[0037] (1) According to the present invention, a device and method for processing threaded holes inside a steam generator are provided. The device and method solve the problem that threaded holes in the narrow space of the supporting flange of the main helium fan of the steam generator are difficult to process, and solve the problem that threaded holes in the narrow space of the supporting flange of the internal component of the steam generator shell cylinder are difficult to process, and can ensure that the verticality and position of the threaded holes obtained by processing meet the requirements of nuclear power equipment;

[0038] (2) The device and method for machining threaded holes inside a steam generator provided by the present invention greatly improve the efficiency of machining threaded holes in a narrow space while ensuring the machining accuracy and position of a single hole, and the economic benefits are remarkable;

[0039] (3) The device and method for processing threaded holes inside a steam generator provided by the present invention have contributed to the manufacture of China's fourth-generation nuclear power high-temperature gas-cooled reactor; they also provide a new solution for the processing of threaded holes inside large cylinders, which can be promoted and applied to other products. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 A schematic diagram showing the overall structure of the device provided by the present application when milling threaded holes on a supporting flange of a main helium blower of a steam generator;

[0041] Figure 2 A schematic diagram showing the overall structure of the device provided by the present application when drilling / tapping threaded holes inside a steam generator cylinder;

[0042] Figure 3 A schematic diagram showing the structure of the turntable mounting bracket on the device provided by the present application is shown;

[0043] Figure 4 A schematic structural diagram of a positioning and fixing bracket of the device provided by the present application when milling threaded holes on a supporting flange of a main helium blower of a steam generator is shown;

[0044] Figure 5 A schematic diagram showing the structure of a positioning and fixing bracket when the device provided by the present application is used to drill / tap threaded holes inside a steam generator cylinder;

[0045] Figure 6 A schematic diagram of the structure of a three-axis CNC thread milling machine provided by the present application is shown;

[0046] Figure 7A schematic diagram of the structure of a drilling machine on a device provided by the present application is shown;

[0047] Figure 8 A schematic diagram of the structure of a tapping machine on a device provided by the present application is shown;

[0048] Fig. 9 A schematic diagram of the structure between the rotating arm and the rotating table base of the device provided by the present application is shown.

[0049] Description of Reference Numerals

[0050] 1-Turntable mounting bracket, 11-Adjustable shim, 12-Centering screw, 2-Turntable base, 21-Positioning and fixing bracket, 211-Through hole, 22-Hole, 23-Annular groove, 24-Servo motor, 25-Locking mechanism, 3-Turntable plate, 31-Swivel arm, 32-Counterweight arm, 321-Electrical cabinet, 33-Bull's eye bearing, 34-Auxiliary support rod, 4-Three-axis linkage CNC thread milling machine, 41-Spindle, 42-Y-axis drive assembly, 43- X-axis drive assembly, 44-Z-axis drive assembly, 45-spindle drive assembly, 6-drilling machine, 61-drilling machine Y-axis servo motor, 62-drilling machine column, 63-drilling machine Z-axis servo motor, 64-drilling machine spindle box, 65-drilling machine spindle servo motor, 66-drilling machine spindle, 7-tapping machine, 71-tapping machine Y-axis servo motor, 72-tapping machine column, 73-tapping spindle box, 74-tapping machine spindle motor, 75-tapping machine spindle. DETAILED DESCRIPTION

[0051] The present invention will be further described in detail below through the accompanying drawings and embodiments. Through these descriptions, the characteristics and advantages of the present invention will become more clear and distinct.

[0052] The word "exemplary" is used exclusively herein to mean "serving as an example, embodiment, or illustration." Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments. Although various aspects of the embodiments are shown in the drawings, the drawings are not necessarily drawn to scale unless otherwise noted.

[0053] The present invention provides a device for processing threaded holes inside a steam generator, such as Figure 1 , Figure 2 and Figure 3 As shown in the figure, the device comprises a turntable mounting bracket 1 and a rotating table base 2, on which 8 adjustable shims 11 are arranged, and the 8 adjustable shims 2 are evenly distributed in a ring shape on the top surface of the turntable mounting bracket 1; the bottom of the turntable mounting bracket 1 can be fixedly mounted on a cast iron platform with a T-slot;

[0054] The rotating table base 2 is mounted on the adjustable shim 11, and the level of the rotating table base 2 is adjusted by the adjustable shim 11; a rotatable threaded rod is provided on the adjustable shim 11, and the top of the adjustable shim 11 can be fine-tuned up and down by rotating the threaded rod, thereby achieving the effect of adjusting the level;

[0055] On the turntable mounting bracket 1, 8 centering screws 12 are evenly arranged around the turntable base 2, and the coaxiality of the rotation center of the turntable base 2 and the rotation center of the device to be processed is adjusted by the centering screws 12; the centering screws 12 are horizontally arranged, one end of the centering screws 12 abuts against the turntable base 2, and the other end of the centering screws 12 extends to the outside of the turntable mounting bracket 1 and can be screwed, and the elongation of the centering screws 12 is controlled by screwing, so that the turntable base 2 is pushed to be fine-tuned in the horizontal direction by the centering screws 12.

[0056] Preferably, a locking mechanism 25 is provided on the turntable base 2 , and when the position of the turntable base 2 is adjusted, the turntable base 2 is locked on the turntable mounting bracket 1 through the locking mechanism 25 .

[0057] like Figure 4 and Figure 5 As shown in the figure, a rotatable rotating table plate 3 is arranged in the middle of the rotating table base 2, and a rotating arm 31 and a counterweight arm 32 that rotate together are arranged on the rotating table plate 3, and a specific processing equipment is arranged on the rotating arm 31; the rotating arm 31 and the counterweight arm 32 are basically located on the same straight line; the rotating arm 31 is relatively long and extends from the top of the turntable mounting bracket 1, so that the main axis of the processing equipment thereon can be located on the outside of the turntable mounting bracket 1.

[0058] Preferably, the rotating table plate 3 is connected to the rotating table base 2 through a slewing support mechanism, and the slewing support mechanism is an inner and outer ring structure, the inner ring is a gear, the inner ring is fixed to the rotating table base 2 by bolts, and the outer ring is fixed to the rotating table plate 3 by bolts. The servo motor 24 is installed on the rotating table plate 3, and at the same time, the output end of the servo motor 24 is directly connected to the cylindrical gear, and the cylindrical gear is meshed with the inner ring gear of the slewing support mechanism. The servo motor 24 provides power to drive the cylindrical gear to rotate, and the cylindrical gear is meshed with the inner ring gear of the slewing support mechanism. Because the inner ring of the slewing support mechanism is fixed to the rotating table base 2, the outer ring of the slewing support mechanism is indirectly driven to rotate, and the rotating table plate 3 is driven to rotate. The parameters of the cylindrical gear are: module 5mm, number of teeth 34, or module 12mm, number of teeth 20.

[0059] In the present application, by controlling the rotation amount of the servo motor 24, the rotation angle of the rotating table 3 can be accurately controlled each time, and the angle can be just the angle between the two threaded holes to be processed. Furthermore, a dividing encoder is provided on the rotating table 3, and the dividing encoder controls the rotating table 3 to rotate at an angle of 360n degrees each time.

[0060] On the turntable base 2, a positioning and fixing bracket 21 is provided on the side of the turntable arm 31, and the positioning and fixing bracket 21 can slide on the turntable base 2 as the turntable arm 31 rotates; the positioning and fixing bracket 21 is cooperated with the turntable base 2 to improve the position accuracy of the threaded hole on the cylinder to be processed.

[0061] Preferably, if Figure 4 and Figure 5 As shown in , n holes 22 are evenly distributed in a ring on the rotating table base 2, and a through hole 211 is opened on the positioning and fixing bracket 21. The cylindrical pin passes through the through hole 211 and the hole 22 to connect and position the rotating arm 31 and the rotating table base 2, thereby improving the stability of the device during processing; n is the number of holes to be processed on the cylinder to be processed. The cross-sectional shape of the through hole 211 is set to be waist-shaped and has a certain curvature, which can allow the cylindrical pin to be inserted into two holes at the same time when the positioning and fixing bracket 21 is rotated to any position; in this application, the rotating arm 31 and the rotating table base 2 are connected by a cylindrical pin, which can offset the vibration generated by a part of the processing equipment during operation, improve the accuracy of hole processing, and ensure that the position of the threaded hole meets the design requirements.

[0062] In a preferred embodiment, a swivel arm support assembly is also provided between the swivel arm 31 and the turntable base 2, and the swivel arm support assembly can slide on the turntable base 2 as the swivel arm 31 rotates. When the processing equipment is working, the swivel arm support assembly provides vertical upward support force for the swivel arm 31.

[0063] Preferably, the swing arm support assembly includes a bull's eye bearing 33 and an auxiliary support rod 34; Fig. 9 As shown in;

[0064] The auxiliary support rod 34 is vertically arranged, one end of which is fixed to the rotating arm 31, and the other end is fixed to the bull's eye bearing 33, and abuts against the rotating table base 2 through the bull's eye bearing 33;

[0065] Preferably, an annular groove 23 is provided on the rotating table base 2, and the bull's eye bearing 33 is embedded in the annular groove 23 and then slides along the annular groove 23;

[0066] Preferably, the vertical height of the auxiliary support rod 34 is adjustable so as to fully abut against the tightening rotating arm 31, ensuring that the rotating arm 31 does not generate deflection in the vertical direction and ensuring that the verticality of the hole to be processed meets the design requirements.

[0067] In a preferred embodiment, Figure 1 As shown in , when the device to be processed is the supporting flange of the main helium blower of the steam generator, the processing equipment is a three-axis CNC thread milling machine 4,

[0068] like Figure 6 As shown in , the three-axis linkage CNC thread milling machine 4 includes a spindle 41, a Y-axis driving assembly 42 for controlling the spindle 41 to move along the Y-axis direction, an X-axis driving assembly 43 for controlling the spindle 41 to move along the X-axis direction, a Z-axis driving assembly 44 for controlling the spindle 41 to move along the Z-axis direction, and a spindle driving assembly 45 for driving the spindle 41 to rotate;

[0069] The Y-axis direction is the radial direction of the rotating table 3 , the Z-axis direction is the axial direction of the rotating table 3 , and the Y-axis direction is perpendicular to the X-axis direction and the Z-axis direction.

[0070] The three-axis linkage CNC thread milling machine in this application is equipped with a non-standard spindle and spindle mounting base. The dimension from the center of the spindle mounting base to the shell surface is 101.5mm, which is suitable for special working conditions with narrow processing space. At the same time, the spindle power part uses a smaller Siemens servo motor 1FK7084-2A71-1RH1_3D-zh.

[0071] In a preferred embodiment, Figure 2 As shown in , when the device to be processed is a supporting flange in a steam generator cylinder, the processing equipment is a drilling machine 6 and a tapping machine 7, and the device for processing threaded holes inside the steam generator cylinder can be referred to as: a device for drilling / tapping threaded holes inside the steam generator cylinder;

[0072] In the device for drilling / tapping threaded holes inside the steam generator cylinder, the drill bit of the drilling machine 6 and the drill bit of the tapping machine 7 can slide along the radial direction of the rotating table 3, that is, the ball screws of the drilling machine 6 and the tapping machine 7 are arranged along the radial direction of the rotating table 3;

[0073] On the rotating arm 31, the line between the axis of the drill bit of the drilling machine 6 and the rotation center of the rotating table 3 is called the drilling machine direction line, and the line between the axis of the drill bit of the tapping machine 7 and the rotation center of the rotating table 3 is called the tapping machine direction line; the angle between the drilling machine direction line and the tapping machine direction line is set to 360n degrees; n is the number of holes that need to be processed on the cylinder to be processed.

[0074] Preferably, the drilling machine 6 and the tapping machine 7 can work independently of each other at the same time. Such a setting enables the drilling machine 6 and the tapping machine 7 to work simultaneously under the premise of ensuring processing accuracy, greatly improving work efficiency, and such a design can reduce the number of rotations of the rotating platen 3, reduce errors, and reduce the possibility of operational errors.

[0075] like Figure 7 As shown in , the drilling machine is provided with a drilling machine Y-axis servo motor 61, and the drilling machine Y-axis servo motor 61 drives the drilling machine column 62 to move radially through the drilling machine Y-axis ball screw pair, and the radial direction is the radial direction of the rotating table 3; the drilling machine Z-axis servo motor 63 is provided on the drilling machine column 62, and the drilling machine Z-axis servo motor 63 drives the drilling machine spindle box 64 to move up and down through the drilling machine Z-axis ball screw pair;

[0076] A drilling machine spindle servo motor 65 is provided on the drilling machine spindle box 64. The drilling machine spindle servo motor 65 drives the drilling machine spindle 66 to rotate through the drilling machine planetary reducer inside the drilling machine transmission box, thereby realizing drilling processing.

[0077] like Figure 8 As shown in the figure, the tapping machine 7 is provided with a tapping machine Y-axis servo motor 71, and the tapping machine Y-axis servo motor 71 drives the tapping machine column 72 to move radially through the tapping machine Y-axis ball screw pair, and the radial direction is the radial direction of the rotating table 3; the dynamic tapping machine column 72 is provided with a tapping spindle box 73, and the tapping spindle box 73 realizes the up and down feeding movement on the tapping machine column 72 through gears and racks;

[0078] A tapping machine spindle motor 74 is provided on the tapping spindle box 73, and the power output by the tapping machine spindle motor 74 is transmitted to the tapping machine spindle 75 through the tapping machine planetary reducer; when processing the thread, the tap is installed on the tapping machine spindle 75, and the tap is manually brought into contact with the bottom hole of the thread through the tapping handwheel. After the tapping starts, the thread processing will be automatically guided until the thread processing is completed. After the lower limit is reached, the processing automatically stops.

[0079] In the drilling machine and tapping machine in the present application, the spindle servo motor and the spindle are connected by a planetary reducer, so that the spindle servo motor can be set closer to the rotation center of the rotating table 3, thereby reducing the structural size outside the spindle and adapting to the working conditions of narrow processing space. Preferably, the drilling machine spindle servo motor 65 and the tapping machine spindle motor 74 use a smaller servo motor MDMF202L1G6. Preferably, the size from the spindle center to the spindle box shell surface of the drilling machine and the tapping machine is set to 51.5mm.

[0080] The present invention also provides a method for machining a threaded hole inside a steam generator, and the method is implemented by the device for machining a threaded hole inside a steam generator as described above.

[0081] Preferably, when the device to be processed is a supporting flange of a main helium blower of a steam generator, the processing equipment is a three-axis CNC thread milling machine 4. The method mills a threaded hole on the supporting flange of a main helium blower of a steam generator. The method comprises the following steps:

[0082] Step 1: The main helium fan support flange of the steam generator is welded to the straight section of the fan casing cylinder and the lower flange of the fan casing cylinder. After overall heat treatment, the main helium fan support flange is aligned and marked, the center positions of n threaded holes to be processed are determined and marked, and then the steam generator cylinder is hoisted onto a cast iron platform with a T-slot;

[0083] Step 2, assembling the device for processing threaded holes inside the steam generator on the outside of the steam generator cylinder; a three-axis linkage CNC thread milling machine 4 is provided on the rotating arm 31 of the device for processing threaded holes inside the steam generator;

[0084] Step 3, hoisting the assembled device for processing threaded holes inside the steam generator into the steam generator cylinder, adjusting the coaxiality and parallelism between the device body and the main helium fan support flange, and fixing them;

[0085] Step 4, aligning the center of the main axis of the three-axis linkage CNC thread milling machine 4 on the device with the center of any threaded hole to be milled; the threaded hole to be milled is the first hole;

[0086] Step 5, connect the rotating arm 31 and the rotating table base 2 by passing a cylindrical pin through the through hole 211 and the hole 22; eliminate the deflection on the rotating arm 31 by adjusting the vertical height of the auxiliary support rod 34;

[0087] Step 6, milling the first threaded hole by a three-axis CNC thread milling machine 4;

[0088] Step 7, take out the cylindrical pin, control the rotating table 3 to rotate 360n degrees, and then insert the cylindrical pin;

[0089] Step 8, milling the second threaded hole by the three-axis CNC thread milling machine 4;

[0090] Step 9, repeat steps 7 and 8 until the milling of all n threaded holes is completed.

[0091] Preferably, in step 2, the following sub-steps are specifically included: installing the turntable base 2 and the turntable plate 3 thereon onto the adjustable shim 11 of the turntable mounting bracket 1, then installing the three-axis linkage CNC thread milling machine 4 onto the turntable arm 31, and installing the electrical cabinet 321 of the electrical control system on the counterweight arm 32.

[0092] Preferably, in step 4, a center is installed on the spindle of the three-axis CNC thread milling machine 4, and alignment is performed by rotating the rotary table 3 and controlling the spindle of the three-axis CNC thread milling machine 4 to slide along the Y-axis direction.

[0093] In a preferred embodiment, when the device to be processed is a supporting flange in a steam generator cylinder, the processing equipment is a drilling machine 6 and a tapping machine 7. The method can be referred to as a method for drilling / tapping threaded holes inside a steam generator cylinder, comprising the following steps:

[0094] Step 1, align and mark the support flange in the steam generator cylinder after welding and heat treatment, determine the center positions of n threaded holes to be processed, mark them, and then hoist the steam generator cylinder onto a cast iron platform with T-slots;

[0095] Step 2, assembling a device for drilling / tapping threaded holes inside the steam generator cylinder on the outside of the steam generator cylinder;

[0096] Step 3, hoisting the assembled device for drilling / tapping threaded holes inside the steam generator cylinder into the steam generator cylinder, adjusting the coaxiality and parallelism between the device body and the steam generator cylinder, and fixing them;

[0097] Step 4, aligning the center of the main shaft of the drilling machine on the device with the center of any threaded hole to be processed; the threaded hole to be processed is the first hole;

[0098] Step 5, connect the rotating arm 31 and the rotating table base 2 by passing a cylindrical pin through the through hole 211 and the hole 22; eliminate the deflection on the rotating arm 31 by adjusting the vertical height of the auxiliary support rod 34;

[0099] Step 6, drilling the first threaded hole and chamfering it by a drilling machine 6;

[0100] Step 7, take out the cylindrical pin, control the rotating table 3 to rotate 360n degrees, and then insert the cylindrical pin;

[0101] Step 8, using a tapping machine 7 to process a threaded hole at the position of the first hole, and at the same time, using a drilling machine 6 to drill a second threaded hole and chamfer it;

[0102] Step 9, repeat steps 7 and 8 until the processing of all n threaded holes is completed.

[0103] Preferably, in step 2, the following sub-steps are specifically included: installing the turntable base 2 and the turntable plate 3 thereon onto the adjustable shim 11 of the turntable mounting bracket 1, then installing the drilling machine 6 and the tapping machine 7 onto the turntable arm 31, and installing the electrical cabinet 321 of the electrical control system on the counterweight arm 32.

[0104] Preferably, in step 4, a center is installed on the main shaft of the drilling machine, and the alignment is performed by rotating the rotary table 3 and controlling the drill bit of the drilling machine 6 to slide along the radial direction of the rotary table 3.

[0105] Example 1

[0106] The main helium fan support flange of the 600MW high-temperature reactor steam generator is welded to the straight section of the fan casing and the lower flange of the fan casing. After heat treatment, the overall height of the fan casing cylinder assembly is nearly 4699mm and the diameter is nearly On the main helium fan support flange inside the cylinder, mark the pitch circle diameter to The center position of 36 M64X3 threaded holes; the inner diameter of the shell cylinder is 2938mm, the distance between the pitch circle of the threaded hole and the inner wall of the cylinder is 110mm, and the space is small; the threaded hole accuracy is very high, verticality: 0.2mm, position accuracy: Thread roughness: Ra3.2μm.

[0107] The present invention provides Figure 1 , Figure 3 , Figure 4 , Figure 5 and Figure 8 The device for processing threaded holes inside the steam generator shown in the figure performs the processing task of the above 36 threaded holes. The specific operation process is as follows:

[0108] Step 1, hoisting the welded steam generator cylinder onto a cast iron platform with a T-slot;

[0109] Step 2, assembling the device for processing threaded holes inside the steam generator on the outside of the steam generator cylinder; a three-axis linkage CNC thread milling machine 4 is provided on the rotating arm 31 of the device for processing threaded holes inside the steam generator;

[0110] Step 3, hoisting the assembled device for processing threaded holes inside the steam generator into the steam generator cylinder, adjusting the coaxiality and parallelism between the device body and the main helium fan support flange, and fixing them;

[0111] Step 4, aligning the center of the main axis of the three-axis linkage CNC thread milling machine 4 on the device with the center of any threaded hole to be milled; the threaded hole to be milled is the first hole;

[0112] Step 5, connect the rotating arm 31 and the rotating table base 2 by passing a cylindrical pin through the through hole 211 and the hole 22; eliminate the deflection on the rotating arm 31 by adjusting the vertical height of the auxiliary support rod 34;

[0113] Step 6, milling the first threaded hole by the three-axis CNC thread milling machine 4; specifically includes the following sub-steps:

[0114] Sub-step 6-1, use a thread milling cutter to rough mill to diameter The hole depth is 126 mm; then, the diameter is milled Finally, mill 3X45° chamfers;

[0115] Sub-step 6-2, use a slotting cutter to machine the backing groove at the bottom of the threaded hole, with a diameter of Depth 12±1mm;

[0116] Sub-step 6-3, use a thread milling cutter to process M64X3 threads. The thread processing is divided into 5 rough milling and 1 fine milling.

[0117] Sub-step 6-4, use a coated M64X3 manual tap to manually go through the processed threaded hole to improve the roughness of the threaded hole;

[0118] Step 7, take out the cylindrical pin, manipulate the rotating table 3 to rotate 10 degrees, and then insert the cylindrical pin;

[0119] Step 8, milling the second threaded hole by the three-axis CNC thread milling machine 4;

[0120] Step 9: Repeat steps 7 and 8 until the milling of all 36 threaded holes is completed.

[0121] Inspection found that the position, verticality and roughness of the 36 milled threaded holes met the requirements of the main helium fan support flange drawings of the high-temperature gas-cooled reactor steam generator and met the assembly requirements of the steam generator as a whole.

[0122] Example 2

[0123] After the 600MW high-temperature steam generator shell cylinder internal component support flange is welded with the upper shell and the shell main flange and other parts, and heat treated, the shell cylinder assembly has an overall height of nearly 7500mm and a diameter of nearly On the flange surface inside the cylinder, draw a line to find the pitch circle diameter. The center position of 36 M42X2 threaded holes; the inner diameter of the shell cylinder is 4419mm, the distance between the pitch circle of the threaded hole and the inner wall of the cylinder is 60mm, and the space is small; the threaded hole precision requirements are very high, verticality: Position degree: Thread roughness: Ra3.2μm.

[0124] The present invention provides Figure 2 , Figure 3 , Figure 4 , Figure 6 , Figure 7and Fig. 9 The device for drilling / tapping threaded holes inside the steam generator cylinder shown in the figure performs the processing task of the above 36 threaded holes. The specific operation process is as follows:

[0125] Step 1, hoisting the steam generator cylinder onto a cast iron platform with T-slots;

[0126] Step 2, assembling a device for drilling / tapping threaded holes inside the steam generator cylinder on the outside of the steam generator cylinder;

[0127] Step 3, hoisting the assembled device for drilling / tapping threaded holes inside the steam generator cylinder into the steam generator cylinder, adjusting the coaxiality and parallelism between the device body and the steam generator cylinder, and fixing them;

[0128] Step 4, aligning the center of the main shaft of the drilling machine on the device with the center of any threaded hole to be processed; the threaded hole to be processed is the first hole;

[0129] Step 5, connect the rotating arm 31 and the rotating table base 2 by passing a cylindrical pin through the through hole 211 and the hole 22; eliminate the deflection on the rotating arm 31 by adjusting the vertical height of the auxiliary support rod 34;

[0130] Step 6, drilling the first threaded hole and chamfering it by a drilling machine 6; specifically includes the following sub-steps:

[0131] Sub-step 6-1, use a twist drill to drill to the diameter Hole depth 100mm;

[0132] Sub-step 6-2, using a reaming needle, expand the hole to a diameter of and

[0133] Sub-step 6-3, use a boring tool to finish the bottom hole of the threaded hole to the diameter

[0134] Sub-step 6-4, using a chamfering tool to process 2X45° chamfers;

[0135] Step 7, take out the cylindrical pin, manipulate the rotating table 3 to rotate 10 degrees, and then insert the cylindrical pin;

[0136] Step 8, using a tapping machine 7 to process a threaded hole at the position of the first hole, and at the same time, using a drilling machine 6 to drill a second threaded hole and chamfer it; wherein the threaded hole processing includes using a drilling-expansion-boring process, first drilling to a diameter of Expand the hole twice and Then replace the boring tool and bore the hole to

[0137] Step 9: Repeat steps 7 and 8 until all 36 threaded holes are processed.

[0138] Inspection found that the position, verticality and roughness of the 36 threaded holes processed met the requirements of the drawings of the internal component support flanges of the shell cylinder of the high-temperature gas-cooled reactor steam generator and met the assembly requirements of the steam generator as a whole.

[0139] The present invention has been described above in conjunction with preferred embodiments, but these embodiments are only exemplary and serve only as an illustration. On this basis, the present invention may be subjected to a variety of substitutions and improvements, all of which fall within the scope of protection of the present invention.

Claims

1. A device for machining threaded holes inside a steam generator, characterized in that: The device comprises a turntable mounting bracket (1) and a rotating table base (2), wherein eight adjustable shims (11) are arranged on the turntable mounting bracket (1), and the eight adjustable shims (2) are evenly distributed in a ring shape on the top surface of the turntable mounting bracket (1); The rotating table base (2) is mounted on the adjustable shim (11), and the horizontality of the rotating table base (2) is adjusted by the adjustable shim (11); On the turntable mounting bracket (1), eight centering screws (12) are evenly arranged around the turntable base (2), and the coaxiality between the rotation center of the turntable base (2) and the rotation center of the main helium blower support flange is adjusted by the centering screws (12); A rotatable rotating table (3) is arranged in the middle of the rotating table base (2); a rotating arm (31) and a counterweight arm (32) which rotate together are arranged on the rotating table (3); and a three-axis linkage CNC thread milling machine (4) is arranged on the rotating arm (31); the main shaft of the three-axis linkage CNC thread milling machine (4) is transported to the top of the threaded hole to be milled on the main helium fan support flange through the rotating table (3) and the rotating arm (31); and the threaded hole is milled on the main helium fan support flange by the three-axis linkage CNC thread milling machine (4).

2. The device for machining threaded holes inside a steam generator according to claim 1, characterized in that: The three-axis linkage CNC thread milling machine (4) comprises a main shaft (41), and also comprises a Y-axis driving assembly (42) for controlling the main shaft (41) to move along the Y-axis direction, an X-axis driving assembly (43) for controlling the main shaft (41) to move along the X-axis direction, a Z-axis driving assembly (44) for controlling the main shaft (41) to move along the Z-axis direction, and a main shaft driving assembly (45) for driving the main shaft (41) to rotate; The Y-axis direction is the radial direction of the rotating table (3), the Z-axis direction is the axial direction of the rotating table (3), and the Y-axis direction is perpendicular to the X-axis direction and the Z-axis direction.

3. The device for machining threaded holes inside a steam generator according to claim 1, characterized in that: A positioning and fixing bracket (21) is arranged above the rotating table base (2) and on the side of the rotating arm (31), and the positioning and fixing bracket (21) can slide on the rotating table base (2) as the rotating arm (31) rotates; A number of n holes (22) are evenly distributed in a ring shape on a rotary table base (2), a through hole (211) is provided on the positioning and fixing bracket (21), and a cylindrical pin passes through the through hole (211) and the hole (22) to connect and position the rotating arm (31) and the rotary table base (2), thereby improving the stability of the three-axis linkage CNC thread milling machine (4) during milling processing; n is the number of holes that need to be processed on the cylinder to be processed.

4. The device for machining threaded holes inside a steam generator according to claim 1, characterized in that: A swivel arm support assembly is also provided between the swivel arm (31) and the swivel table base (2). The swivel arm support assembly can slide on the swivel table base (2) as the swivel arm (31) rotates. When the three-axis linkage CNC thread milling machine (4) is working, the swivel arm support assembly provides a vertical upward supporting force for the swivel arm (31).

5. The device for machining threaded holes inside a steam generator according to claim 4, characterized in that: The rotating arm support assembly comprises a bull's eye bearing (33) and an auxiliary support rod (34); The auxiliary support rod (34) is vertically arranged, one end of which is fixed to the rotating arm (31), and the other end of which is fixed to the bull's eye bearing (33), and abuts against the rotating table base (2) through the bull's eye bearing (33); Preferably, an annular groove (23) is provided on the rotating table base (2), and the bull's eye bearing (33) is embedded in the annular groove (23) and then slides along the annular groove (23); Preferably, the vertical height of the auxiliary support rod (34) is adjustable.

6. The device for machining threaded holes inside a steam generator according to claim 1, characterized in that: A graduation encoder is arranged on the rotating table (3), and the graduation encoder is used to control the rotating table (3) to rotate at an angle of 360n degrees each time.

7. A method for machining threaded holes inside a steam generator, characterized in that: The method mills threaded holes on the supporting flange of the main helium blower of the steam generator, and the method is realized by the device for processing threaded holes inside the steam generator as claimed in any one of claims 1-6.

8. The method for machining threaded holes inside a steam generator according to claim 7, characterized in that: The method comprises the following steps: Step 1: The main helium fan support flange of the steam generator is welded to the straight section of the fan casing cylinder and the lower flange of the fan casing cylinder. After overall heat treatment, the main helium fan support flange is aligned and marked, the center positions of n threaded holes to be processed are determined and marked, and then the welded steam generator cylinder is hoisted onto a cast iron platform with a T-slot; Step 2, assembling the device for milling threaded holes on the supporting flange of the main helium blower of the steam generator on the outside of the steam generator cylinder; Step 3, hoisting the assembled device for milling threaded holes on the main helium fan support flange of the steam generator into the interior of the steam generator cylinder, adjusting the coaxiality and parallelism between the device body and the main helium fan support flange, and fixing them; Step 4, aligning the center of the main shaft of the three-axis linkage CNC thread milling machine (4) on the device with the center of any threaded hole to be milled; the threaded hole to be milled is the first hole; Step 5, connecting the rotating arm (31) and the rotating table base (2) by passing a cylindrical pin through the through hole (211) and the hole (22); eliminating the deflection on the rotating arm (31) by adjusting the vertical height of the auxiliary support rod (34); Step 6, milling the first threaded hole by a three-axis CNC thread milling machine (4); Step 7, remove the cylindrical pin, manipulate the rotating table (3) to rotate 360 ​​degrees, and then insert the cylindrical pin; Step 8, milling a second threaded hole by a three-axis CNC thread milling machine (4); Step 9, repeat steps 7 and 8 until the milling of all n threaded holes is completed.

9. The method for machining threaded holes inside a steam generator according to claim 8, characterized in that: In step 2, the following sub-steps are specifically included: installing the turntable base (2) and the turntable plate (3) thereon onto the adjustable pad (11) of the turntable mounting bracket (1), then installing the three-axis linkage CNC thread milling machine (4) onto the turntable arm (31), and installing the electrical cabinet of the electrical control system onto the counterweight arm (32).

10. The method for machining threaded holes inside a steam generator according to claim 8, characterized in that: In step 4, a center is installed on the spindle of the three-axis CNC thread milling machine (4), and alignment is performed by rotating the rotary table (3) and controlling the spindle of the three-axis CNC thread milling machine (4) to slide along the Y-axis direction.

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