Wheel disc mortise milling process and wheel disc clamping and dividing device

Abstract

The milling process of the wheel disc mortise comprises the following steps: roughly milling an upper section of the mortise; roughly milling a straight groove and an inclined surface of the mortise; the middle throat part is roughed, the allowance of the middle throat part is formed and milled through a T-shaped milling cutter, and the allowance of the opening area of the middle throat part is further removed; forming and rough milling are carried out on the middle throat part, forming and milling are carried out, and an irregular allowance area in rough milling is removed; performing semi-finish milling and forming milling; semi-finishing molded lines of a middle throat part and a bottom part; carrying out semi-finish milling on an area; the upper section is subjected to finish milling through an upper section polishing tool; eccentric finish milling; a smooth-edge eccentric finish milling cutter is used for completing single-side milling; finish-milling the bottom molded line: finish-milling the bottom molded line; a wheel disc clamping and dividing device for machining wheel disc mortises comprises a dividing rotary table, a transition disc, a circular pressing plate, a double-end stud, a circular mandrel and a nut. A transition disc is mounted on the indexing turntable, and a hole and a groove are pre-formed in the transition disc; end face teeth are arranged on the upper portion of the transition disc and used for meshing with the wheel disc to transmit torque after automatic centering and positioning.

Description

Technical Field

[0001] The invention belongs to the technical field of processing the tenon and groove of a gas turbine wheel disc, and in particular relates to a milling process for the tenon and groove of a wheel disc and a wheel disc clamping and indexing device. Background Art

[0002] The gas turbine impeller is one of the important components of the gas turbine, usually used to fix the blades and transmit torque; the main functions of the impeller include:

[0003] Fixed blades: The wheel disc is connected to the blades through the mortise and tenon, and the blades are firmly fixed on the wheel disc; the blades are installed on the outer edge of the wheel disc, and the rotation of the wheel disc drives the blades to rotate at high speed;

[0004] Torque transmission: The impeller is connected to the shaft of the gas turbine and is responsible for converting the high-temperature and high-pressure gas kinetic energy generated by the combustion of gas into mechanical energy, and transmitting this energy to the shaft of the gas turbine through the impeller, thereby driving the generator or other mechanical devices;

[0005] Withstand high temperature and high pressure environment: Since the wheel disc is in a high temperature and high pressure working environment, it is usually made of high-strength heat-resistant materials to ensure long-term use under harsh conditions;

[0006] The tenon and groove of a gas turbine wheel refers to the connection structure between the wheel and the blades, which has the following functions:

[0007] Blade installation and fixation: The tenon is designed to match the tenon at the bottom of the blade. The blade is inserted into the tenon of the wheel disc through the tenon to achieve the installation and fixation of the blade. This design enables the blade to withstand huge centrifugal force without falling off.

[0008] Stress distribution: The tongue and groove design usually takes into account the reasonable distribution of stress, so that the stress generated by the blade during operation is evenly distributed on the disc, avoiding local stress concentration, thereby extending the life of the disc and blades;

[0009] Disassembly and maintenance: The tongue-and-groove structure usually allows the blades to be disassembled and replaced, making maintenance and overhaul easier; thus, when a blade is damaged or the disc needs maintenance, it can be easily disassembled without affecting the operation of the entire gas turbine;

[0010] At present, there are two commonly used processing methods for gas turbine wheel mortise and tenon:

[0011] 1. Broaching: According to the mortise and tenon profile, a special broach is equipped and the mortise and tenon broaching process is completed on a special broaching machine to meet the requirements of the drawing;

[0012] 2. Milling: Equip a special milling cutter according to the mortise and tenon profile, and complete the milling of the mortise and tenon on a boring machine with a turntable to meet the requirements of the drawing.

[0013] Both of the above methods can realize the processing of the tenon and groove, but they both have shortcomings for the circumferentially distributed wheel tenon and groove:

[0014] 1. For broaching, first of all, you need machine tools dedicated to wheel broaching. In addition, you need to configure corresponding broaches according to different profiles. Under existing technical conditions, the cost of a set of broaches for a single profile is about 1.5 million, which is very expensive.

[0015] 2. Milling: The tool cost is relatively low, but the wheel disc lacks special clamping tooling when clamped on the boring machine. The manual adjustment of the wheel disc centering time is long, and the general boring machine turntable does not have a graduation monitoring device, and the graduation accuracy of the mortise and tenon cannot be guaranteed. Non-special equipment clamping cannot guarantee the rigidity of the wheel disc, the cutting resistance is large during milling, and the dimensional accuracy and smoothness of the mortise and tenon groove are difficult to guarantee.

[0016] The tenon and groove of the turbine wheel disc can be processed by CNC broaching machine, which has high broaching efficiency and easy surface quality control. The commonly used machine tools in the industry are imported German Hoffman five-axis vertical broaching machines, and the price of a single machine tool is about 2000W. At the same time, broaching requires special broaches, and each set of broaches can only correspond to one profile. The broaches are expensive, and the price of a set is about 1.5 million. For large-scale parts processing, it can improve processing efficiency and better meet the processing cycle. In continuous production, the use of CNC broaching machines or five-axis vertical broaching machines has production advantages and the accuracy of the products is guaranteed;

[0017] However, for parts with smaller batches, such as the tenons of a single batch of gas turbine wheel discs with a single specification, the broaching solution is expensive. At the same time, since broaches are special tools, if the number of parts is small, the cost of the tool cannot be amortized to the later units. Therefore, for a small number of wheels, the cost of the machine tools and tools used for broaching are very high, resulting in extremely high production costs, which cannot meet the market needs and the demand for gas turbine maintenance and replacement parts;

[0018] There are also some processing methods that refer to the processing method of turbine rotor wheel grooves and perform milling on CNC double-head milling machines. The machine tool is equipped with two milling spindles and one indexing spindle. It is a four-axis machine tool. The current unit price of high-precision heavy-duty CNC double-head milling machines is around 1000W. In CNC double-head milling, it is necessary to design tooling, and use the tooling to effectively connect the wheel disc with the machine tool indexing spindle. It is necessary to ensure that the center line of the wheel disc coincides with the rotation center line of the machine tool indexing spindle. At the same time, the tooling provides a support position for the machine tool. According to the characteristics of the parts, the tooling should consist of three parts: tie rods, transition plates and tie rod nuts. These three toolings need to be fixed with special hydraulic tensioners. There are several difficulties in this solution: 1. The tension setting of the hydraulic tensioner. When the mortise and tenon milling, the axial force is large, and the wheel disc relies on the tension generated by the hydraulic tensioner to mesh together through the end face teeth. The tension of the tensioner must be greater than the milling force to ensure that the parts will not loosen during processing. The meshing part of the part will be deformed due to excessive tension. Therefore, the tension needs to be determined through special research. 2 The hydraulic tensioner is designed for special tension, so it is necessary to purchase a hydraulic tensioner specifically for this set of tooling, which is costly. Therefore, under the premise of high-cost machine tools and tooling, the clamping method of this milling solution is unreliable and it is difficult to achieve the precision requirements of mortise and tenon milling.

[0019] In the prior art, the processing of the wheel tenon groove is generally carried out by broaching, which requires special broaching machine equipment and special broaches. The technical preparation cycle and cost are very high. It is suitable for large-scale production and processing, but it is difficult to meet the requirements for single-piece small-batch processing.

[0020] Center tie rod gas turbine rotor 1( Figure 1 ) by tie rod nut 2( Figure 1 )、Center tie rod 3( Figure 1 ) and multiple roulette wheels 4 ( Figure 1 ) and other parts, and each wheel has end face teeth 5 ( Figure 1 ). For details on the end face gear structure, see Figure 2 There are 180 teeth on each end face, evenly distributed along the circumference.

[0021] In the center tie rod 3 ( Figure 1 ) under the tensioning force, each wheel 4 ( Figure 1 ) through the end face gear 5( Figure 1 , Figure 2 ) mesh with each other, the end face teeth 5( Figure 1 , Figure 2 ) can realize automatic centering, accurate positioning and torque transmission.

[0022] Roulette 4 ( Figure 1 ) structure such as Figure 3 As shown, both end faces have end face teeth 5 ( Figure 3 ) structure, multiple tongue and groove 6 are evenly distributed around the circumference ( Figure 3 ). The mortise and tenon 6-type line is as follows Figure 4 As shown, it is mainly divided into three parts: the upper section 7, the middle throat 8 and the bottom profile 9. At the same time, the mortise angle α and the axial positioning dimension L are as shown in Figure 5 As shown, there are high requirements for the mortise and tenon profile dimensional accuracy, positioning dimensional accuracy and circumferential distribution accuracy.

[0023] Therefore, on ordinary milling machine tools, that is, CNC three-axis milling machines, how to achieve milling instead of broaching to complete the processing of gas turbine wheel disc tenon and groove, reduce production equipment requirements, and thus reduce production costs, there is a lack of mature processing technology;

[0024] In general, the above-mentioned existing technologies have technical defects such as insufficient production capacity of broaching machines and high cost of broaches, and are in urgent need of improvement. Summary of the invention

[0025] In order to overcome the above problems of the prior art and achieve the above objectives and other related objectives, the present application provides a milling process for a wheel tenon groove, comprising the following steps:

[0026] S1, rough milling the upper section of the mortise and tenon groove, and leaving allowances on both sides of the upper section;

[0027] S2, rough milling of straight grooves and inclined surfaces of the mortise and tenon grooves, where the allowances of the bottom profile and the narrowest area of ​​the middle throat are the same;

[0028] S3, roughing the middle throat, using a T-type milling cutter to form milling to machine the middle throat allowance, and further remove the allowance in the middle throat opening area;

[0029] S4, forming rough milling of the middle throat, forming milling, removing the irregular allowance area in the rough milling, making the middle throat allowance uniform;

[0030] S5, semi-finishing milling and profile milling; semi-finishing the middle throat and bottom profile; semi-finishing milling area;

[0031] S6, upper section polishing cutter, fine milling of the upper section;

[0032] S7, eccentric finishing milling, using profile eccentric milling, the eccentricity is 0.3mm; use a smooth edge eccentric finishing milling cutter to complete single-side milling, the eccentricity between the tool centerline and the mortise centerline during milling is 0.3mm, and the width of the middle throat of the eccentric finishing milling is 0.6mm;

[0033] S8, bottom profile finishing milling, bottom profile finishing milling.

[0034] The present application provides a milling process technology solution for the wheel tenon groove, which also has the following technical features:

[0035] Preferably, in one embodiment of the present application, in S2, a corrugated edge milling cutter is used to profile the bottom profile line and the middle throat rough milling area.

[0036] Preferably, in one embodiment of the present application, in S3, a T-type milling cutter is used for processing.

[0037] Preferably, in one embodiment of the present application, in S5, a single-sided margin of 0.4 mm to 0.6 mm is left in the area of ​​the middle throat and the bottom profile.

[0038] Preferably, in one embodiment of the present application, in S5, the semi-finishing milling cutter is a corrugated blade.

[0039] Preferably, in one embodiment of the present application, in S6, the layer cutting reverse milling process is performed, and the tool used is a smooth-edge milling cutter.

[0040] Preferably, in one embodiment of the present application, in S7, before eccentric milling, the milling depth is kept the same, and center milling is performed first to remove the allowance on both sides, that is, a 0.3mm allowance is maintained on both sides, and then eccentric milling is performed on both sides, and a smooth-blade eccentric finishing milling cutter is used to complete single-side milling. During milling, the eccentricity between the center line of the tool and the center line of the mortise and tenon is 0.3mm, and the width of the middle throat of the eccentric finishing milling is 0.6mm.

[0041] Preferably, in one embodiment of the present application, in S8, the bottom profile finishing cutter performs forming milling to complete the milling process of the entire mortise and tenon.

[0042] A wheel disc clamping and indexing device for wheel disc tenon and groove processing comprises an indexing turntable, a transition disc, a circular pressure plate, a double-headed stud, a circular core shaft and a nut; the transition disc is installed on the indexing turntable, and holes and grooves are pre-opened on the transition disc; end face teeth are provided on the upper part of the transition disc for automatically centering and positioning the meshing wheel disc to transmit torque; fasteners and a rotation limit shaft are provided on the wheel disc to enable the wheel disc to achieve indexing rotation; holes or grooves are opened on the upper part of the indexing turntable for fixing.

[0043] The present application provides a technical solution for a wheel disc clamping and indexing device for processing a wheel disc tenon groove, and also has the following technical features:

[0044] Preferably, in one embodiment of the present application, a graduation monitoring device is provided on the wheel disc clamping graduation device, and the graduation monitoring device comprises a graduation transmission rod, a circular grating, a bracket, a square box and an adjusting screw;

[0045] The circular pressure plate fastens the wheel disc by adjusting screws; a graduation transfer rod is arranged on the upper end surface of the circular pressure plate, so that the graduation transfer rod rotates together with the entire wheel disc or the wheel disc clamping graduation device; the upper end of the graduation transfer rod passes through the bracket, and a circular grating is arranged on the upper end; the bracket is supported by a square box.

[0046] Preferably, in one embodiment of the present application, the circular grating, the graduation transfer rod and the wheel clamping graduation device are concentrically arranged.

[0047] Preferably, in one embodiment of the present application, the circular grating is used to monitor the division of the wheel; the division monitoring device is externally connected to a display device for displaying current angle information.

[0048] The beneficial effects of this application are:

[0049] 1. The processing cost of the present invention is low. Compared with the tool cost of broaching, which is as high as one million yuan, the processing tools and tooling used in the present invention are low in price. The cost of a complete set of processing tools does not exceed 100,000 yuan. Moreover, the tooling such as the indexing turntable and the transition plate are all existing equipment, and the total tooling cost is low.

[0050] 2. The present invention has low vibration during the machining process. By optimizing the tool solution, especially adding a T-type milling cutter and a small-head milling cutter during rough milling, the machining allowance of each step is reduced. The use of a corrugated edge milling cutter during rough milling reduces the cutting resistance of the entire machining process.

[0051] 3. The mortise and tenon processed by the present invention has good dimensional accuracy and surface roughness. A smooth-blade eccentric milling cutter is used for fine milling, and profiling milling is used instead of forming milling to reduce tool wear and better ensure dimensional accuracy and surface roughness.

[0052] 4. The workpiece of the present invention is accurately installed and positioned, and is convenient to calibrate. The self-centering of the end face teeth realizes automatic centering and accurate positioning, and the entire calibration process is relatively convenient;

[0053] 5. The present invention has high precision in processing circumferential indexing. By installing an indexing monitoring device, the indexing error can be monitored in real time to ensure the indexing accuracy.

[0054] 6. The milling processing method of the present application optimizes the milling tool solution, reduces cutting resistance, ensures the dimensional accuracy and smoothness of the mortise and tenon, and reduces tool costs; at the same time, it provides a set of clamping and indexing devices, and uses the self-centering characteristics of the end face tooth structure of the wheel to design a transition plate tooling as a transition device between the turntable and the wheel, so as to achieve accurate positioning of the wheel clamping, and at the same time rely on the engagement of the end face teeth to transmit the turntable torque to complete the indexing; in addition, a circular grating indexing monitoring device is added to monitor the wheel indexing in real time to ensure the indexing accuracy of the mortise and tenon processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 A schematic diagram of a center tie rod type gas turbine rotor of a wheel disc tenon groove milling process of the present invention;

[0056] Figure 2 A schematic diagram of the end face tooth structure of a wheel disc tenon groove in a milling process of a wheel disc tenon groove of the present invention;

[0057] Figure 3 A schematic diagram of a wheel structure of a wheel tenon groove of a wheel tenon groove of the present invention;

[0058] Figure 4 A schematic diagram of the tenon structure of a wheel disc tenon in the milling process of the present invention;

[0059] Figure 5 A schematic diagram of the arrangement dimensions of the tenon and groove of a wheel disc tenon and groove of the present invention;

[0060] Figure 6 It is a schematic diagram of the rough milling upper opening of a milling process of a wheel disc tenon groove of the present invention;

[0061] Figure 7 A schematic diagram of a corn milling cutter for a milling process of a wheel disc tenon groove of the present invention;

[0062] Figure 8 It is a schematic diagram of rough milling straight groove and inclined surface of a milling process of a wheel plate tenon groove of the present invention;

[0063] Fig. 9 A schematic diagram of a corrugated edge milling cutter for a milling process of a wheel disc tenon groove according to the present invention;

[0064] Fig.10 A schematic diagram of roughing the middle throat of a wheel disc tenon groove milling process of the present invention;

[0065] Fig.11 A schematic diagram of a T-type milling cutter for a milling process of a wheel tenon groove of the present invention;

[0066] Fig.12 It is a schematic diagram of rough milling of the middle throat portion of a milling process of a wheel disc tenon groove of the present invention;

[0067] Fig.13 A schematic diagram of a small-head rough milling cutter for a milling process of a wheel disc tenon groove of the present invention;

[0068] Fig.14 A schematic diagram of semi-finishing milling of a milling process for a wheel disc tenon groove of the present invention;

[0069] Fig.15 A schematic diagram of a corrugated blade semi-finishing milling cutter for a milling process of a wheel tenon groove of the present invention;

[0070] Fig.16 A schematic diagram of an upper section light cutter in a milling process of a wheel disc tenon groove according to the present invention;

[0071] Fig.17 A schematic diagram of eccentric precision milling of a milling process for a wheel disc tenon groove of the present invention;

[0072] Fig.18A schematic diagram of a smooth-blade eccentric fine milling cutter for a milling process of a wheel tenon groove of the present invention;

[0073] Fig.19 It is a schematic diagram of the bottom profile fine milling of a milling process of a wheel disc tenon groove of the present invention;

[0074] Fig. 20 It is a schematic diagram of a bottom profile finishing cutter in a milling process of a wheel disc tenon groove of the present invention;

[0075] Fig.21 A schematic diagram of a wheel disc clamping and indexing device for processing a wheel disc tenon groove of the present invention Figure 1 ;

[0076] Fig. 22 A schematic diagram of a wheel disc clamping and indexing device for processing a wheel disc tenon groove of the present invention Figure 2 ;

[0077] Fig.23 A schematic diagram of a wheel disc clamping and indexing device for processing a wheel disc tenon groove of the present invention Figure 3 ;

[0078] Fig.24 It is a transition plate of a wheel disc clamping and indexing device for processing a wheel disc tenon groove of the present invention;

[0079] Components in the picture:

[0080] 1. Center-pull-rod gas turbine rotor

[0081] 2. Tie rod nut

[0082] 3. Center tie rod

[0083] 4. Roulette

[0084] 5. Face teeth

[0085] 6. Mortise and tenon

[0086] 7. Upper section

[0087] 8. Middle throat

[0088] 9. Bottom profile

[0089] 10. Rough milling allowance of the upper section

[0090] 11. Corn milling cutter

[0091] 12. Middle throat rough milling area

[0092] 13. Corrugated edge milling cutter

[0093] 14. Middle throat opening area margin

[0094] 15. T-type milling cutter

[0095] 16. Semi-finishing milling cutter

[0096] 17. Small head rough milling cutter

[0097] 18. Semi-finishing milling area

[0098] 19. Semi-fine Knife

[0099] 20. Smooth edge milling cutter

[0100] 21. Light-blade eccentric finishing milling cutter

[0101] 22. Bottom profile finishing knife

[0102] 23. Indexing table

[0103] 24. Transition plate

[0104] 25. Round pressure plate

[0105] 26. Indexing transfer rod

[0106] 27. Circular grating

[0107] 28. Bracket

[0108] 29. Square Box

[0109] 30. Double-ended studs

[0110] 31. Round mandrel

[0111] 32. Nut

[0112] 33. Adjust the screw. DETAILED DESCRIPTION

[0113] The specific implementation methods of the present application are further described in detail below in conjunction with the accompanying drawings. These implementation methods are only used to illustrate the present application, and are not intended to limit the present invention.

[0114] In the description of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0115] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0116] Furthermore, in the description of the present invention, unless otherwise specified, “plurality” means two or more.

[0117] like Figure 1-20 , a milling process of a wheel disc tenon groove comprises the following steps:

[0118] S1, rough milling the upper section 7 of the mortise and tenon 6, and leaving margins on both sides of the upper section 7;

[0119] S2, rough milling of the straight groove and the inclined surface of the tenon groove 6, wherein the allowances of the bottom profile 9 and the narrowest area of ​​the middle throat 8 are the same;

[0120] S3, roughing the middle throat 8, using a T-shaped milling cutter 15 to form and mill the middle throat 8, and further removing the middle throat opening area margin 14;

[0121] S4, rough milling of the middle throat 8, forming milling; removing the irregular margin area in the rough milling step to make the margin of the middle throat 8 uniform, that is, removing the irregular margin area in the rough milling to make the margin of the middle throat 8 uniform

[0122] S5, semi-finishing milling and profile milling; semi-finishing the middle throat 8 and the bottom profile 9; semi-finishing milling area 18;

[0123] S6, upper section 7 polishing tool, fine milling of upper section 7;

[0124] S7, eccentric finishing milling, using profile eccentric milling, the eccentricity is 0.3mm; use the smooth edge eccentric finishing milling cutter 21 to complete the single-side milling, the eccentricity between the center line of the tool and the center line of the tenon groove 6 during milling is 0.3mm, and the width of the middle throat 8 of the eccentric finishing milling is 0.6mm;

[0125] S8, finish milling of bottom profile 9, finish milling of bottom profile 9.

[0126] Specifically, in one embodiment of the present application, in S2 , a corrugated edge milling cutter 13 is used to profile the bottom profile line 9 and the middle throat rough milling area 12 .

[0127] Specifically, in one embodiment of the present application, in S3, a T-type milling cutter 15 is used for processing.

[0128] Specifically, in one embodiment of the present application, in S5 , a single-sided margin of 0.4 mm is left in the area of ​​the middle throat portion 8 and the bottom profile line 9 .

[0129] Specifically, in one embodiment of the present application, in S5, the semi-finishing milling cutter 16 is a corrugated blade.

[0130] Specifically, in one embodiment of the present application, in S6 , the layer cutting reverse milling process is performed, and the tool used is a smooth edge milling cutter 20 .

[0131] Specifically, in one embodiment of the present application, in S7, before eccentric milling, the milling depth is kept the same, center milling is performed first to remove the excess on both sides, that is, a 0.3 mm excess is maintained on both sides, and then eccentric milling is performed on both sides.

[0132] Specifically, in one embodiment of the present application, in S8 , the bottom profile finishing cutter 22 performs forming milling to complete the milling process of the entire mortise and tenon 6 .

[0133] Specifically, in one embodiment of the present application, a wheel disc 4 clamping and indexing device with a processed tenon groove 6 includes a dividing turntable 23, a transition plate 24, a circular pressure plate 25, a double-headed stud 30, a circular core shaft 31 and a nut 32; the transition plate 24 is installed on the dividing turntable 23, and the transition plate 24 is pre-opened with holes and grooves; the upper part of the transition plate 24 is provided with end face teeth 5, which are used to automatically find the center and position the wheel disc 4 to transmit torque; fasteners and a rotation limit shaft are provided on the wheel disc 4, so that the wheel disc 4 can achieve dividing rotation; the upper part of the dividing turntable 23 has holes or grooves for fixing.

[0134] Specifically, in one embodiment of the present application, a graduation monitoring device is provided on the wheel disc 4 clamping graduation device, and the graduation monitoring device includes a graduation transmission rod 26, a circular grating 27, a bracket 28, a square box 29 and an adjusting screw 33;

[0135] The circular pressure plate 25 is fastened to the wheel disc 4 by means of an adjusting screw 33; a graduation transfer rod 26 is arranged on the upper end surface of the circular pressure plate 25, so that the graduation transfer rod 26 rotates together with the entire wheel disc 4 or the graduation device clamping the wheel disc 4; the upper end of the graduation transfer rod 26 passes through the bracket 28, and a circular grating 27 is arranged on the upper end; the bracket 28 is supported by a square box 29.

[0136] Specifically, in one embodiment of the present application, the circular grating 27, the graduation transfer rod 26 and the wheel 4 clamping graduation device are arranged concentrically.

[0137] Specifically, in one embodiment of the present application, the circular grating 27 is used to monitor the division of the wheel 4; the division monitoring device is externally connected to a display device for displaying current angle information.

[0138] A milling process for a wheel disc tenon and groove is composed of four parts: a gas turbine wheel disc and tenon and groove, a tenon and groove milling processing plan, a wheel disc clamping and indexing device, and an indexing monitoring device.

[0139] Gas turbine wheel 4( Figure 3 ) Multiple mortises 6 are evenly distributed along the circumference ( Figure 3 , Figure 4 ), mortise and tenon 6( Figure 5 ) on the roulette wheel. Figure 5 As shown, there is an angle α between the rotation centerline of the wheel and the centerline of the tenon groove, and the intersection of the two centerlines is at a distance L from the left end face. Both ends of the wheel have end face gear structures, end face gear 5 ( Figure 1 , Figure 2 ) can realize the mutual meshing between the wheels, automatic centering, accurate positioning and torque transmission. Before the mortise and tenon processing, the end face tooth structure has been processed.

[0140] 2. The mortise and tenon milling process is divided into 8 steps:

[0141] 1) Rough milling of the upper section, leaving allowance on both sides, see Figure 6 . Use corn milling cutter 11 ( Figure 6 , Figure 7 ) proceed to the upper measure 7( Figure 6 ) area rough milling, using the layer cutting profiling method to remove the upper section rough milling allowance 10( Figure 6 ), leaving a margin in the upper measure 7.

[0142] 2) Rough milling of straight grooves and inclined surfaces, where the bottom profile 9 and the narrowest area of ​​the middle throat 8 have the same allowance, such as Figure 8 As shown. Use corrugated edge milling cutter 13 ( Fig. 9 ) Profiling the bottom profile and the middle throat rough milling area 12 ( Figure 8 ), improve the efficiency of rough milling.

[0143] 3) Roughen the middle throat, use T-type milling cutter to form milling and process the middle throat 8 allowance, and further remove the middle throat opening area allowance 14 ( Fig.10 ),like Fig.10 As shown. Using T-type milling cutter 15 ( Fig.10 , Fig.11 ) for processing, reducing the subsequent tool processing allowance and reducing cutting resistance.

[0144] 4) Middle throat forming rough milling, forming milling, using small head rough milling cutter 17 ( Fig.12 , Fig.13 ) Remove the irregular margin area 16 ( Fig.12 ) to ensure uniform margin in the middle throat.

[0145] 5) Semi-finishing milling, forming milling, semi-finishing middle throat 8 ( Fig.14 ) and bottom line 9( Fig.14 ), all areas have a single-sided margin of 0.4mm, semi-finishing area 18 see Fig.14 , Semi-finishing milling cutter 16, see Fig.14 The semi-finishing milling cutter has a corrugated edge and has smaller cutting resistance.

[0146] 6) Upper section polishing knife, fine milling upper section 7 ( Fig.16 ), using layer cutting reverse milling, the tool is a smooth edge milling cutter 20 ( Fig.16 ) to ensure the size and surface roughness of the upper section.

[0147] 7) Eccentric fine milling, using profile eccentric milling, the eccentricity is 0.3mm, such as Fig.17 When milling, the eccentricity between the center line of the tool and the center line of the mortise and tenon is 0.3 mm, and the eccentric finishing milling of the middle throat is 8 ( Fig.17 ) width is 0.6mm, which is larger than the allowance of 0.4mm, and the smooth edge eccentric finishing milling cutter 21 ( Fig.17 , Fig.18 ) Single-sided milling is achieved, and the cutting resistance is small, which is conducive to ensuring the dimensional accuracy and surface roughness of the tenon 6, and also reduces tool wear. In order to further reduce the resistance, before eccentric milling, the milling depth is kept the same, and the center milling is performed first, and the margin on both sides is further removed, that is, the margin on both sides is kept at 0.3mm, and then the eccentric milling on both sides is performed.

[0148] 8) Finish milling of bottom profile, finish milling of bottom profile 9( Fig.19 ), using bottom profile finishing knife 22 ( Fig.19 , Fig. 20 ) to perform forming milling to complete the milling process of the entire mortise and tenon 6.

[0149] 3. Wheel clamping and indexing device.

[0150] like Fig.21 , Fig. 22 , Fig.23 As shown, the wheel clamping indexing device consists of an indexing turntable 23, a transition plate 24, a circular pressure plate 25, a stud 30 ( Fig. 22 )、Circular mandrel 31( Fig. 22 ) and nut 32( Fig. 22 )composition.

[0151] The entire wheel clamping indexing device is powered by the indexing turntable 23. It can be indexed manually or linked with the machine tool, and the machine tool CNC system sends instructions to complete the indexing. The transition plate 24 is installed on the indexing turntable 23. When installing, pay attention to adjusting the concentricity of the two. The transition plate 24 ( Fig.24) is pre-opened with holes and grooves, and can be fixed to the indexing turntable by bolts. The bolt form is not fixed and can be determined according to the hole or groove form on the upper part of the indexing turntable 23.

[0152] like Fig.24 As shown, the upper part of the transition plate 24 is also provided with end face teeth 5 ( Fig.24 ), this structure is consistent with the end face teeth 5 on both sides of the wheel disc ( Figure 2 , Figure 3 ) are the same, so if Fig. 22 As shown, the transition plate 24 can mesh with the wheel plate 4 through the end face teeth 5 to achieve automatic centering, accurate positioning and torque transmission.

[0153] In order to achieve stability when placing the wheel, the stud 30 ( Fig. 22 )、Circular mandrel 31( Fig. 22 ) for installation, where the stud 30 ( Fig. 22 ) and nut 32( Fig. 22 ) provides the necessary tension for the entire clamping and indexing device. The circular mandrel 31 ( Fig. 22 ) and the central pull rod 3( Figure 1 ) are similar and have similar diameters, which are slightly smaller than the inner diameter of the wheel disc, making it easier to find the center when hoisting the wheel disc. Fig. 22 )、Circular mandrel 31( Fig. 22 ) After the installation is completed, the wheel disc can be hoisted so that the center hole of the wheel disc is fitted on the circular core shaft 31 ( Fig. 22 ) and then slowly lower it, fine-tune the angle of the wheel disc so that the lower end face teeth 5 of the wheel disc are fully meshed with the upper end face teeth 5 of the transition plate, and complete the wheel disc hoisting. At this time, the wheel disc and the turntable remain concentric. Then put the circular pressure plate 25 ( Fig. 22 ), tighten nut 32( Fig. 22 ) to complete the installation of the entire wheel clamping and indexing device.

[0154] 4. Graduation monitoring device.

[0155] like Fig.21 , Fig. 22 , Fig.23 As shown, the graduation monitoring device is composed of a graduation transmission rod 26, a circular grating 27, a bracket 28, a square box 29 and an adjusting screw 33.

[0156] The indexing transmission rod 26 is placed on the circular pressure plate 25, and the concentricity is adjusted by 6 adjusting screws 33. At the same time, the 6 adjusting screws 33 correspond to the nuts 32 ( Fig. 22) can transmit torque after tightening, which will drive the indexing transmission rod 26 to rotate together with the entire wheel clamping indexing device. The upper part of the indexing transmission rod 26 is connected to the circular grating 27, and the circular grating 27 is fixed by a square box 29 and a bracket 28. When installing the entire indexing monitoring device, it is necessary to ensure that the circular grating 27, the indexing transmission rod 26 and the wheel clamping indexing device are concentric. During use, an external display device is required to display the current angle information.

[0157] Specifically, in one embodiment of the present application, a milling processing method and a clamping and indexing device for the tenon groove of a gas turbine wheel disc are provided. The milling processing method reduces cutting resistance by optimizing the milling tool scheme, ensures the dimensional accuracy and smoothness of the tenon groove, and reduces the tool cost. At the same time, a clamping and indexing device is provided. The self-centering characteristics of the end face tooth structure of the wheel disc are used to design a transition plate tooling as a transition device between the turntable and the wheel disc, so as to achieve accurate positioning of the wheel disc clamping, and at the same time rely on the meshing of the end face teeth to transmit the turntable torque to complete the indexing. In addition, a circular grating indexing monitoring device is added to monitor the wheel disc indexing in real time to ensure the indexing accuracy of the tenon groove processing.

[0158] Specifically, in one embodiment of the present application, the roulette wheel 4 ( Figure 3 ) After completing the end face tooth 5 ( Figure 2 ) After grinding, you can start the mortise and tenon 6 ( Figure 4 ) milling work. In CNC boring machine or milling machine processing, the first step is to build the wheel clamping indexing device, hoist the indexing turntable 23 ( Fig. 22 ) onto the machine table, calibrate and ensure that the turntable is in a horizontal state, and then hoist the transition plate 24 ( Fig. 22 )、Stud 30( Fig. 22 )、Circular mandrel 31( Fig. 22 ), install and fix them respectively. Lifting wheel 4( Fig. 22 ), so that the center hole of the wheel disc 4 is mounted on the circular mandrel 31 ( Fig. 22 ) for preliminary positioning, to the lower side end face tooth 5 of the wheel disc 4 ( Fig. 22 ) When the wheel disc 4 is close to the upper end face teeth 5 of the transition plate, fine-tune the angle of the wheel disc 4 so that the wheel disc and the end face teeth of the transition plate are meshed with each other, and then slowly lower the wheel disc 4 to complete the wheel disc hoisting. At this time, re-measure the runout and horizontal position of the wheel disc 4. If they meet the requirements, hoist the circular pressure plate 25 ( Fig. 22 ), and tighten nut 32( Fig. 22 ) to complete the construction of the wheel clamping and indexing device.

[0159] Build a graduation monitoring device, the graduation transmission rod 26 is placed on the circular pressure plate 25, and the six adjustment screws 33 correspond to the nuts 32 ( Fig. 22 ) six faces, and the concentricity is adjusted by tightening the adjusting screws 33. Then the square box 29 ( Fig.23 ) and bracket 28( Fig.23 ), place the circular grating 27 ( Fig.23 ), pay attention to adjusting the concentricity of the circular grating 27 and the graduation transfer rod 26 during the installation process.

[0160] Formal processing begins, the indexing turntable 23 is indexed according to the mortise and tenon indexing table. After the indexing is completed, the mortise and tenon indexing table and the circular grating angle display are checked. After confirmation, the tool can be installed and the corresponding CNC program can be called for milling processing. The angle, structural size and positioning size of the mortise and tenon are guaranteed by the CNC program.

[0161] According to the 8 steps in the above-mentioned tenon and groove milling process plan, the wheel disc is milled with the tenon and groove:

[0162] 1) Rough milling of the upper section, leaving allowance on both sides, see Figure 6 . Use corn milling cutter 11 ( Figure 6 , Figure 7 ) proceed to the upper measure 7( Figure 6 ) area rough milling, using the layer cutting profiling method to remove the upper section rough milling allowance 10( Figure 6 ), leaving a margin in the upper measure 7.

[0163] 2) Rough milling of straight grooves and inclined surfaces, where the bottom profile 9 and the narrowest area of ​​the middle throat 8 are left with the same allowance, such as Figure 8 As shown. Use corrugated edge milling cutter 13 ( Fig. 9 ) Profiling the bottom profile and the middle throat rough milling area 12 ( Figure 8 ), improve the efficiency of rough milling.

[0164] 3) Roughen the middle throat, use T-type milling cutter to form milling and process the middle throat 8 allowance, and further remove the middle throat opening area allowance 14 ( Fig.10 ),like Fig.10 As shown. Using T-type milling cutter 15 ( Fig.10 , Fig.11 ) for processing, reducing the subsequent tool processing allowance and reducing cutting resistance.

[0165] 4) Middle throat forming rough milling, forming milling, using small head rough milling cutter 17 ( Fig.12 , Fig.13 ) Remove the irregular margin area 16 ( Fig.12 ) to ensure uniform margin in the middle throat.

[0166] 5) Semi-finishing milling, forming milling, semi-finishing middle throat 8 ( Fig.14 ) and bottom line 9( Fig.14 ), all areas have a single-sided margin of 0.4mm, semi-finishing area 18 see Fig.14 , Semi-finishing milling cutter 16, see Fig.14The semi-finishing milling cutter has a corrugated edge and has smaller cutting resistance.

[0167] 6) Upper section polishing knife, fine milling upper section 7 ( Fig.16 ), using layer cutting reverse milling, the tool is a smooth edge milling cutter 20 ( Fig.16 ) to ensure the size and surface roughness of the upper section.

[0168] 7) Eccentric fine milling, using profile eccentric milling, the eccentricity is 0.3mm, such as Fig.17 When milling, the eccentricity between the center line of the tool and the center line of the mortise and tenon is 0.3 mm, and the eccentric finishing milling of the middle throat is 8 ( Fig.17 ) width is 0.6mm, which is larger than the allowance of 0.4mm, and the smooth edge eccentric finishing milling cutter 21 ( Fig.17 , Fig.18 ) Single-sided milling is achieved, and the cutting resistance is small, which is conducive to ensuring the dimensional accuracy and surface roughness of the tenon 6, and also reduces tool wear. In order to further reduce the resistance, before eccentric milling, the milling depth is kept the same, and the center milling is performed first, and the margin on both sides is further removed, that is, the margin on both sides is kept at 0.3mm, and then the eccentric milling on both sides is performed.

[0169] 8) Finish milling of bottom profile, finish milling of bottom profile 9( Fig.19 ), using bottom profile finishing knife 22 ( Fig.19 , Fig. 20 ) to perform forming milling to complete the milling process of the entire mortise and tenon 6.

[0170] After the first mortise is processed in each step, the size and surface roughness need to be checked. After confirmation, the indexing is performed to complete the milling of the next mortise in the current step until the milling of all mortise in the current step is completed. Then the tool for the next step is replaced to perform the milling of the next step, and the above process is repeated to complete the operation of 8 steps.

[0171] The mortise and tenon indexing table and the circular grating angle display must be checked after each turntable indexing. The mortise and tenon size, surface roughness and tool wear must be checked regularly during the machining process. Every 3-5 mortise and tenons should be checked during rough milling and semi-finishing milling, and each mortise and tenon should be checked during fine milling.

[0172] The present invention adopts an ordinary three-axis CNC floor-standing boring and milling machine for processing. The unit price of a CNC floor-standing boring and milling machine with a spindle specification of 200 is about 200W, and the machine tool cost is relatively low. When the wheel is clamped, the center line is perpendicular to the ground, and the cutting force generated by the tool during processing is borne by the ground, so a large clamping force is not required. Relatively speaking, the tool cost is lower and it is easier to implement. The total cost of the high-precision turntable, clamping tool, indexing feedback device, etc. involved in the present invention is about 50W, the tool cost is 10W, and the processing cost is low. The disadvantage is that in order to reduce cutting resistance and ensure the dimensional accuracy and smoothness of the mortise and tenon, the milling tool scheme is optimized, resulting in an increase in milling steps, and the processing cycle is twice that of the broaching machine processing.

[0173] In summary, the present invention solves the difficult problem of machining the mortise and tenon of a wheel disc on an ordinary three-axis CNC milling machine. Compared with multi-axis high-end machine tools such as a five-axis vertical broaching machine and a four-axis double-head milling machine, the present invention has a lower machining cost, but a longer machining cycle and is suitable for single-piece and small-batch machining.

[0174] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principles of the present invention. These improvements and substitutions should also be regarded as the scope of protection of the present invention.

Claims

1. A milling process for a wheel mortise and tenon, characterized in that: The steps include: S1, rough milling the upper section of the mortise and tenon groove, and leaving allowances on both sides of the upper section; S2, rough milling of straight grooves and inclined surfaces of the mortise and tenon grooves, where the allowances of the bottom profile and the narrowest area of ​​the middle throat are the same; S3, roughing the middle throat, using a T-type milling cutter to form milling to machine the middle throat allowance, and further remove the allowance in the middle throat opening area; S4, forming rough milling of the middle throat, forming milling, removing the irregular allowance area in the rough milling, making the middle throat allowance uniform; S5, semi-finishing milling and profile milling; semi-finishing the middle throat and bottom profile; semi-finishing milling area; S6, upper section polishing cutter, fine milling of the upper section; S7, eccentric finishing, using profile eccentric milling; S8, bottom profile finishing milling, bottom profile finishing milling.

2. A milling process for a wheel disc tenon groove as claimed in claim 1, characterized in that: In S2, a corrugated edge milling cutter is used to profile the bottom profile and the middle throat rough milling area.

3. A milling process for a wheel disc tenon groove as claimed in claim 1, characterized in that: In S3, a T-type milling cutter is used for processing.

4. A milling process for a wheel disc tenon groove as claimed in claim 1, characterized in that: In S5, a single-sided allowance of 0.4 to 0.6 mm is left in the middle throat and bottom profile area; the semi-finishing milling cutter has a corrugated blade.

5. The milling process of the wheel disc tenon groove according to claim 1, characterized in that: In S6, layer cutting and reverse milling are performed, and a smooth-edge milling cutter is used as the tool.

6. A milling process for a wheel disc tenon groove as claimed in claim 1, characterized in that: In S7, before eccentric milling, the milling depth is kept the same, and center milling is performed first to remove the allowance on both sides, that is, a 0.3mm allowance is maintained on both sides, and then eccentric milling is performed on both sides. A smooth-blade eccentric finishing milling cutter is used to complete single-side milling. During milling, the eccentricity between the tool center line and the mortise center line is 0.3mm, and the width of the middle throat of the eccentric finishing milling is 0.6mm.

7. The milling process of a wheel disc tenon groove according to claim 1, characterized in that: In S8, the bottom profile finishing cutter performs forming milling to complete the milling of the entire mortise and tenon.

8. A wheel clamping and indexing device for processing a wheel tenon groove, using a wheel tenon groove milling process as claimed in claims 1 to 7, characterized in that: It includes a dividing turntable, a transition plate, a circular pressure plate, a double-headed stud, a circular core shaft and a nut; the transition plate is installed on the dividing turntable, and holes and grooves are pre-opened on the transition plate; the upper part of the transition plate is provided with end face teeth, which are used for automatically finding the center and then engaging the wheel to transmit torque; fasteners and a rotation limit shaft are arranged on the wheel to enable the wheel to achieve dividing rotation; holes or grooves are opened on the upper part of the dividing turntable for fixing.

9. A wheel disc clamping and indexing device for wheel disc tenon and groove processing as claimed in claim 8, characterized in that: A graduation monitoring device is arranged on the wheel clamping graduation device, and the graduation monitoring device comprises a graduation transmission rod, a circular grating, a bracket, a square box and an adjusting screw; The circular pressure plate fastens the wheel disc by adjusting screws; a graduation transfer rod is arranged on the upper end surface of the circular pressure plate, so that the graduation transfer rod rotates together with the entire wheel disc or the wheel disc clamping graduation device; the upper end of the graduation transfer rod passes through the bracket, and a circular grating is arranged on the upper end; the bracket is supported by a square box.

10. A wheel disc clamping and indexing device for wheel disc tenon and groove processing as claimed in claim 8, characterized in that: The circular grating, the indexing transmission rod and the wheel clamping indexing device are arranged concentrically; the circular grating is used to monitor the wheel indexing; the indexing monitoring device is externally connected to a display device for displaying current angle information.

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