Clamping tool and clamping method for processing small rotor conifer wheel groove

Abstract

This invention provides a clamping fixture and method for machining fir tree-shaped grooves on a small rotor. The clamping fixture includes a transition plate with a mounting groove on its first end face and a mounting boss on its second end face; an extension shaft with a mounting hole at its first end that matches the mounting boss and a connecting flange at its second end; a first locating pin hole and a first countersunk hole on the bottom wall of the mounting groove; a second locating pin hole and a first connecting through hole on the second end face of the transition plate, located around the mounting boss; a pin hole corresponding to the second locating pin hole and a threaded hole corresponding to the first connecting through hole on the first end face of the extension shaft; and at least two second connecting through holes on the connecting flange. This invention solves the problem in the prior art where small rotors cannot meet the clamping requirements for groove milling due to dimensional interference.

Description

Technical Field

[0001] This invention relates to the field of steam turbine machining technology, and in particular to a clamping fixture and clamping method for machining the fir tree-shaped grooves of a small rotor. Background Technology

[0002] The intermediate impeller of a steam turbine rotor is generally designed with uniformly distributed, discontinuous fir tree-shaped grooves. When machining with a double-head blade root milling machine, the conventional clamping scheme for the steam turbine rotor is to connect the front end of the rotor to the indexing head of the machine tool, and drive the rotor to rotate by the indexing head of the machine tool. Each of the front and rear journals of the rotor is supported by a hydrostatic bracket, which uses hydrostatic oil film support to ensure the rigidity of the workpiece support.

[0003] However, for marine, helium turbine, and chemical-driven steam turbine units, the rotor size is generally small, such as Figure 1 As shown, the axial distances between the front journal 101 of the rotor 100 and the rotor impeller 102 at the end and middle of the rotor 100 are too short. When clamping such small steam turbine rotors, this causes frequent interference between the front hydrostatic support and the machine tool indexing head and tool post, thus failing to meet the clamping and machining requirements for rotor groove milling. Therefore, it is urgent to design a clamping fixture suitable for milling fir tree-shaped grooves on small steam turbine rotors. Summary of the Invention

[0004] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a clamping fixture and clamping method for machining fir tree-shaped wheel grooves of small rotors, so as to solve the problem that small rotors cannot meet the clamping requirements for wheel groove milling due to dimensional interference in the prior art.

[0005] To achieve the above and other related objectives, a first aspect of the present invention provides a clamping fixture for machining the fir tree-shaped groove of a small rotor. The clamping fixture includes a transition plate, a first end face of which is provided with an assembly groove, and a second end face of which is provided with an assembly boss; an extension shaft, a first end of which is provided with an assembly hole adapted to the assembly boss, and a second end of which is provided with a connecting flange; a first locating pin hole and a first countersunk hole are provided on the bottom wall of the assembly groove; a second locating pin hole and a first connecting through hole are provided on the second end face of the transition plate, located around the assembly boss; a pin hole corresponding to the second locating pin hole and a threaded hole corresponding to the first connecting through hole are provided on the first end face of the extension shaft; and at least two second connecting through holes are provided on the connecting flange.

[0006] Preferably, there are two first positioning pin holes and six first countersunk holes.

[0007] Preferably, there are two second positioning pin holes and four first connecting through holes.

[0008] Another aspect of the present invention provides a clamping method using the above-described clamping fixture for machining small rotor fir tree-shaped wheel grooves, the clamping method comprising the following steps:

[0009] S1. Lift the transition plate and heat the assembly groove on the first end face of the transition plate until the diameter of the assembly groove meets the heat fitting requirements.

[0010] S2. The front end of the rotor is embedded in the mounting groove on the first end face of the transition plate, and the first positioning pin hole and the first countersunk hole on the mounting groove correspond to the positioning pin hole and the threaded hole provided at the front end of the rotor, respectively. The first positioning pin is embedded in the first positioning pin hole, and the first fastening screw is pre-installed in the first countersunk hole to ensure that the bottom wall of the mounting groove is close to the end face of the rotor. After the transition plate has completely cooled down, the first positioning pin is tightened and the first fastening screw is tightened.

[0011] S3. Lift the rotor with the transition plate assembled onto a CNC lathe and heat the assembly hole at the first end of the long shaft until the diameter of the assembly hole meets the heat fitting requirements.

[0012] S4. The mounting boss on the second end face of the transition plate is embedded in the mounting hole at the first end of the extension shaft, and the second positioning pin hole and the first connecting through hole on the second end face of the transition plate correspond to the pin hole and the threaded hole on the first end face of the extension shaft, respectively. The second positioning pin is embedded in the second positioning pin hole, and the second fastening screw is pre-installed in the first connecting through hole to ensure that the first end face of the extension shaft is close to the second end face of the transition plate. After the extension shaft has completely cooled down, the second positioning pin is tightened and the second fastening screw is tightened.

[0013] S5. Adjust the extended shaft on a CNC lathe to ensure that the concentricity of the extended shaft and the rotor is within 0.02mm.

[0014] S6. Hoist the rotor with the extended shaft assembled and adjusted to the wheel groove milling machine. Connect the connecting flange at the second end of the extended shaft to the indexing plate of the wheel groove milling machine. Set a front hydrostatic bracket at the extended shaft position to support the front end of the rotor, and set a rear hydrostatic bracket at the rear journal of the rotor to support the rear end of the rotor.

[0015] Preferably, in step S1, "heating the assembly groove on the first end face of the transition plate until the diameter of the assembly groove meets the heat fitting requirements" specifically means: uniformly heating the assembly groove with a flame gun until the diameter of the assembly groove increases by 0.05-0.1mm.

[0016] Preferably, in step S3, "heating the assembly hole at the first end of the connecting long shaft until the diameter of the assembly hole meets the heat fitting requirements" specifically means: uniformly heating the assembly hole at the first end of the connecting long shaft using a flame gun until the diameter of the assembly hole increases by 0.05-0.1mm.

[0017] Preferably, four T-slots are provided on the indexing plate along the radial direction of the indexing plate. The four T-slots are evenly distributed along the circumferential direction of the indexing plate. T-blocks are embedded in two mutually symmetrical T-slots. The T-blocks are provided with threaded holes and connecting screws are provided in the threaded holes. In step S6, "connecting the connecting flange provided at the second end of the extension shaft to the indexing plate of the wheel groove milling machine" specifically means: fitting a transmission pin sleeve in the through hole provided on the connecting flange, passing the connecting screw through the transmission pin sleeve, and putting a washer on the end of the connecting screw and screwing on a nut to completely tighten the connecting flange and the indexing plate.

[0018] As described above, the clamping fixture and clamping method for machining the fir tree-shaped groove of a small rotor according to the present invention have the following beneficial effects: In use, the front end of the rotor is first connected and installed in the mounting groove on the first end face of the transition plate, and then connected to the mounting boss on the second end face of the transition plate through the mounting hole provided at the first end of the extension shaft. Thus, the extension shaft and the rotor are connected to form a whole through the transition plate, thereby lengthening the front end of the rotor. In this way, the front hydrostatic bracket originally supported at the front axle journal of the rotor can be transferred to the extension shaft, thereby increasing the axial clearance space, meeting the requirements of milling the fir tree-shaped groove of the rotor, and the structure is simple and the operation is convenient. Attached Figure Description

[0019] Figure 1 The diagram shown is a structural schematic of the rotor provided by the present invention.

[0020] Figure 2 The diagram shown is a structural schematic of the transition disk provided by the present invention.

[0021] Figure 3 The diagram shown is a structural schematic of the extension shaft provided by the present invention.

[0022] Figure 4 The diagram shown is a schematic diagram of the connection and assembly of the rotor and the transition disk provided by the present invention.

[0023] Figure 5 The diagram shown is a schematic diagram of the connection and assembly of the transition disk and the extension shaft provided by the present invention.

[0024] Figure 6 The diagram shown is a schematic diagram of the connection and assembly of the extension shaft and the indexing plate provided by the present invention.

[0025] Figure 7 The present invention provides Figure 6 Enlarged view of point D in the middle.

[0026] Figure 8 The diagram shown is a structural schematic of the indexing disk provided by the present invention.

[0027] Figure 9 The diagram shown illustrates the use of the clamping fixture provided by this invention.

[0028] Explanation of reference numerals in the attached figures

[0029] 10 Transition Plate

[0030] 11 Assembly Groove

[0031] 12. Assembly boss

[0032] 110 First locating pin hole

[0033] 111 First countersunk hole

[0034] 120 Second locating pin hole

[0035] 121 First connecting through hole

[0036] 20 Extended Shaft

[0037] 21 Assembly Holes

[0038] 22 Connecting flange

[0039] 221 Transmission pin sleeve

[0040] 222 gasket

[0041] 223 Fastening nut

[0042] 201 Pin Hole

[0043] 202 Threaded Hole

[0044] 220 Second connecting through hole

[0045] 1101 First positioning pin

[0046] 1111 First fastening screw

[0047] 1201 Second positioning pin

[0048] 1211 Second fastening screw

[0049] 200-division dial

[0050] 200a T-slot

[0051] 200b connecting screw

[0052] 100 rotors

[0053] 101 Front axle journal

[0054] 102 Rotor Impeller

[0055] 300 Wheel Groove Milling Machine

[0056] 301 Front Static Pressure Bracket

[0057] 302 rear static pressure bracket Detailed Implementation

[0058] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0059] The terms "first" and "second," etc., used in the specification and drawings of this application are used to distinguish different objects or to distinguish different treatments of the same object, rather than to describe a specific order of objects.

[0060] Furthermore, the terms "comprising" and "having," and any variations thereof, used in the description of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the steps or units listed, but may optionally include other steps or units not listed, or may optionally include other steps or units inherent to such process, method, product, or apparatus.

[0061] Before discussing the exemplary embodiments in more detail, it should be noted that some exemplary embodiments are described as processes or methods depicted as flowcharts. Although the flowcharts describe the operations (or steps) as sequential processes, many of these operations can be performed in parallel, concurrently, or simultaneously. Furthermore, the order of the operations can be rearranged. The process can be terminated when its operation is completed, but may also have additional steps not included in the figures. The process can correspond to a method, function, procedure, subroutine, subroutine, etc. Moreover, embodiments and features in the embodiments of the present invention can be combined with each other without conflict.

[0062] Please see Figures 1 to 9It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of the present invention. Therefore, the drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0063] like Figure 1 The diagram shows the structure of a rotor 100 for a marine steam turbine, a helium turbine, and a chemical-driven steam turbine. Due to the generally small size of such small rotors, the axial distance between the front journal 101 of the rotor 100 and the front end of the rotor 100 and the rotor impeller 102 located in the middle of the rotor 100 is too short, which brings significant clamping difficulties to the milling of the fir tree-shaped wheel groove of such small rotors.

[0064] In response to the above problems, such as Figures 2 to 3 As shown, the present invention provides a clamping fixture for machining the fir tree-shaped groove of a small rotor. The clamping fixture includes a transition plate 10 and an extension shaft 20. The first end face of the transition plate 10 is provided with a mounting groove 11, and the second end face of the transition plate 10 is provided with a mounting boss 12. A first locating pin hole 110 and a first countersunk hole 111 are provided on the bottom wall of the mounting groove 11. A second locating pin hole 120 and a first connecting through hole 120 are provided on the second end face of the transition plate 10, located around the mounting boss 12. 21; The first end face of the extension shaft 20 is provided with an assembly hole 21 that matches the assembly boss 12 on the second end face of the transition plate 10, and the first end face of the extension shaft 20 is provided with a pin hole 201 corresponding to the second positioning pin hole 120, and the first end face of the extension shaft 20 is also provided with a threaded hole 202 corresponding to the first connecting through hole 121; the second end of the extension shaft 20 is provided with a connecting flange 22, and the connecting flange 22 is provided with at least two second connecting through holes 220.

[0065] When using the clamping fixture of the present invention, such as Figure 8 As shown, the front end of the rotor 100 is first connected and installed in the mounting groove 11 on the first end face of the transition plate 10. The extension shaft 20 is connected to the mounting boss 12 on the second end face of the transition plate 10 through the mounting hole 21 provided at the first end. Thus, the extension shaft 20 and the rotor 100 are connected to form a whole through the transition plate 10, thereby lengthening the front end of the rotor 100. In this way, the front static pressure bracket 301, which was originally supported at the front journal of the rotor, can be transferred to the extension shaft 20, thereby increasing the axial clearance space, meeting the requirements of the milling of the rotor fir tree-shaped wheel groove, and the structure is simple and easy to operate.

[0066] Specifically, when connecting and installing the rotor 100 to the transition plate 10 at the front end, such as Figure 4As shown, the assembly groove 11 on the first end face of the transition plate 10 needs to be heated first to ensure that the diameter of the assembly groove 11 meets the interference fit requirement of the heat fitting, i.e., until the diameter of the assembly groove 11 increases by 0.05-0.1 mm. Then, the front end of the rotor 100 is nested in the assembly groove 11, so that the rotor and the assembly groove 11 have a certain amount of interference fit. When the front end of the rotor 100 is nested in the assembly groove 11, the first positioning pin hole 110 and the first countersunk hole 111 on the assembly groove 11 are respectively aligned with the positioning pin hole and the threaded hole at the front end of the rotor 100. Correspondingly; then, the first positioning pin 1101 is driven into the first positioning pin hole 110 (so that the first positioning pin 1101 is embedded in the first positioning pin hole 110 on the transition plate 10 and the positioning pin hole provided on the rotor), and the first fastening screw 1111 is pre-installed in the first countersunk hole 111, that is, the first fastening screw 1111 screwed into the first countersunk hole 111 on the transition plate 10 and the threaded hole on the rotor is pre-tightened to ensure that the bottom wall of the assembly groove 11 is in close contact with the end face of the rotor. Then, after the transition plate 10 has completely cooled down, the first positioning pin 1101 is tightened and the first fastening screw 1111 is tightened.

[0067] Preferably, to ensure the stability of the connection between the transition disk 10 and the rotor 100, such as Figure 2 As shown, in this embodiment, two first positioning pin holes 110 are provided on the bottom wall of the mounting groove 11 on the transition plate 10, and the two first positioning pin holes 110 are symmetrically distributed at 180°. Six first countersunk holes 111 are provided on the bottom wall of the mounting groove 11 on the transition plate 10, and the six first countersunk holes 111 are evenly distributed along the circumferential direction of the transition plate 10.

[0068] Specifically, when connecting and installing the extension shaft 20 and the transition plate 10, such as Figure 5As shown, the mounting hole 21 at the first end of the connecting long shaft 20 is first heated to ensure that the diameter of the mounting hole 21 meets the interference fit requirement of the heat fitting, i.e., until the diameter of the mounting hole 21 increases by 0.05-0.1 mm. Then, the mounting boss 12 on the second end face of the transition plate 20 is nested in the mounting hole 21, so that the mounting boss 12 and the mounting hole 21 have a certain amount of interference fit. When the mounting boss 12 and the mounting hole 21 are mated and nested, the second positioning pin hole 120 and the first connecting through hole 121 on the second end face of the transition plate 10 correspond to the pin hole 201 and the threaded hole 202 on the first end face of the transition long shaft 20, respectively. Then, the second positioning pin 1201 is driven into the second positioning pin hole 120 (so that the second positioning pin 1201 is embedded in the second positioning pin hole 120 on the transition plate 10 and the pin hole 201 on the extension shaft 20), and the second fastening screw 1211 is pre-installed in the first connecting through hole 121, that is, the second fastening screw 1211 screwed into the first connecting through hole 121 on the transition plate 10 and the threaded hole 202 on the extension shaft 20 is pre-tightened to ensure that the first end face of the extension shaft 20 is in close contact with the second end face of the transition plate 10. Then, after the extension shaft 20 has completely cooled down, the second positioning pin 1201 is tightened and the second fastening screw 1211 is tightened.

[0069] Preferably, to ensure the stability of the connection and installation between the extension shaft 20 and the transition plate 10, such as Figure 2 As shown, in this embodiment, the transition disk 10 is provided with two second positioning pin holes 120, and the two second positioning pin holes 120 are symmetrically distributed at 180°. The transition disk 10 is provided with four first connecting through holes 121, and the four first connecting through holes 121 are evenly distributed at intervals along the circumferential direction of the transition disk 10.

[0070] Another aspect of the present invention provides a clamping method using the clamping fixture for machining the small rotor fir tree-shaped wheel groove as described above, the clamping method comprising the following steps:

[0071] S1. Lift the transition plate and heat the assembly groove on the first end face of the transition plate until the diameter of the assembly groove meets the heat fitting requirements.

[0072] Specifically, in step S1, "heating the assembly groove 11 on the first end face of the transition disk 10 until the diameter of the assembly groove 11 meets the heat fitting requirements" means: uniformly heating the assembly groove 11 with a flame gun until the diameter of the assembly groove 11 increases by 0.05-0.1mm. This operation heats the assembly groove 11 using the principle of thermal expansion and contraction, facilitating the fitting of the rotor 100 with the assembly groove 11 on the transition disk 10. Furthermore, to ensure the rigidity and firmness of the connection between the transition disk and the rotor, the assembly groove and the rotor employ a certain amount of interference fit.

[0073] S2. The front end of the rotor is embedded in the mounting groove on the first end face of the transition plate, and the first positioning pin hole and the first countersunk hole on the mounting groove correspond to the positioning pin hole and the threaded hole provided at the front end of the rotor, respectively. The first positioning pin is embedded in the first positioning pin hole, and the first fastening screw is pre-installed in the first countersunk hole to ensure that the bottom wall of the mounting groove is close to the end face of the rotor. After the transition plate has completely cooled down, the first positioning pin is tightened and the first fastening screw is tightened.

[0074] S3. Lift the rotor with the transition plate assembled onto a CNC lathe and heat the assembly hole at the first end of the long shaft until the diameter of the assembly hole meets the heat fitting requirements.

[0075] Specifically, in step S3, "heating the mounting hole 21 at the first end of the connecting long shaft 20 until the diameter of the mounting hole 21 meets the heat fitting requirements" means: uniformly heating the mounting hole 21 at the first end of the connecting long shaft 20 using a flame gun until the diameter of the mounting hole 21 increases by 0.05-0.1mm. Through this operation, the mounting hole 21 is heated first using the principle of thermal expansion and contraction, thereby facilitating the fitting of the mounting boss 12 on the second end face of the transition plate 10 with the mounting hole 21 on the connecting long shaft 20. In order to ensure the rigidity and firmness of the connection between the connecting long shaft 20 and the transition plate 10, the mounting hole 21 and the mounting boss 12 adopt a certain amount of interference fit.

[0076] S4. The mounting boss on the second end face of the transition plate is embedded in the mounting hole at the first end of the extension shaft, and the second positioning pin hole and the first connecting through hole 121 on the second end face of the transition plate correspond to the pin hole 201 and the threaded hole 202 on the first end face of the extension shaft 20, respectively. The second positioning pin is embedded in the second positioning pin hole, and the second fastening screw is pre-installed in the first connecting through hole 121 to ensure that the first end face of the extension shaft is close to the second end face of the transition plate. After the extension shaft has completely cooled down, the second positioning pin is tightened and the second fastening screw is tightened.

[0077] S5. Adjust the extended shaft on a CNC lathe to ensure that the concentricity of the extended shaft and the rotor is within 0.02mm.

[0078] Specifically, in step S5, the calibration method is to use a CNC lathe to cut and correct the outer circle of the connecting shaft to ensure that the concentricity of the connecting shaft and the rotor is within 0.02mm.

[0079] S6. Hoist the rotor with the extended shaft assembled and adjusted to the wheel groove milling machine. Connect the connecting flange at the second end of the extended shaft to the indexing plate of the wheel groove milling machine. Set a front static pressure bracket 301 at the extended shaft position to support the front end of the rotor. Set a rear static pressure bracket 302 at the rear journal of the rotor to support the rear end of the rotor.

[0080] Specifically, such as Figure 7 The diagram shows the structure of the indexing plate 200 of the wheel groove milling machine 300. Along the radial direction of the indexing plate 200, four T-slots 200a are provided. These four T-slots 220a are evenly distributed along the circumferential direction of the indexing plate 200. T-blocks are embedded in two mutually symmetrical T-slots 200a, and threaded holes are provided on these T-blocks. Figure 6 As shown, a connecting screw 200b is connected in the threaded hole. In step S6, the step of "connecting the connecting flange 22 at the second end of the extension shaft 20 to the indexing plate 200 of the wheel groove milling machine 300" specifically means: Figure 7 As shown, a transmission pin sleeve 221 is fitted into the through hole 220 provided on the connecting flange 22, and the connecting screw 200b connected to the T-block is passed through the transmission pin sleeve 221. A washer 222 is fitted onto the end of the connecting screw 200b and a fastening nut 223 is screwed on to completely fit the connecting flange 22 with the indexing plate 200 of the wheel groove milling machine.

[0081] In summary, the clamping fixture and method for machining fir tree-shaped wheel grooves of small rotors of the present invention can solve the problem of small rotors being unable to meet the clamping requirements for wheel groove milling due to dimensional interference. By adding an extension method of "extending shaft + transition plate", the clearance space is increased. At the same time, the structure of this clamping fixture can meet the clamping requirements of rotors of different sizes. Even if the rotor end size changes, only a new transition plate needs to be redesigned. The extending shaft is universal, which greatly reduces the tooling cost. Moreover, the clamping fixture has a simple structure and the clamping method is convenient to operate. Operators only need to follow the assembly sequence to complete the installation work without special training. Furthermore, by using a thermally fitted interference fit between the extending shaft and the transition plate, and between the transition plate and the rotor, the three are connected into a rigid whole, which has high safety and machining rigidity, and helps to improve the safety and vibration resistance of subsequent wheel groove milling. Therefore, the present invention effectively overcomes the various shortcomings of the prior art and has high industrial application value.

[0082] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A clamping method using a clamping fixture for machining small rotor fir tree-shaped wheel grooves, characterized in that, The clamping fixture for machining the small rotor fir tree-shaped wheel groove includes: The transition plate has an assembly groove on its first end face and an assembly boss on its second end face. An extension shaft is provided at its first end, which is provided with an assembly hole that matches the assembly boss, and at its second end, which is provided with a connecting flange. The bottom wall of the assembly groove is provided with a first positioning pin hole and a first countersunk hole; the second end face of the transition plate, located around the assembly boss, is provided with a second positioning pin hole and a first connecting through hole. The first end face of the extension shaft is provided with a pin hole corresponding to the second positioning pin hole and a threaded hole corresponding to the first connecting through hole; the connecting flange is provided with at least two second connecting through holes; The clamping method includes the following steps: S1. Lift the transition plate and heat the assembly groove on the first end face of the transition plate until the diameter of the assembly groove meets the heat fitting requirements. S2. The front end of the rotor is embedded in the mounting groove on the first end face of the transition plate, and the first positioning pin hole on the mounting groove corresponds to the positioning pin hole provided at the front end of the rotor, and the first countersunk hole on the mounting groove corresponds to the threaded hole provided at the front end of the rotor. The first positioning pin is embedded in the first positioning pin hole, and the first fastening screw is pre-installed in the first countersunk hole to ensure that the bottom wall of the mounting groove is in close contact with the end face of the rotor. After the transition plate has completely cooled down, the first positioning pin is tightened and the first fastening screw is tightened. S3. Lift the rotor with the transition plate assembled onto a CNC lathe and heat the assembly hole at the first end of the long shaft until the diameter of the assembly hole meets the heat fitting requirements. S4. The mounting boss on the second end face of the transition plate is embedded in the mounting hole at the first end of the extension shaft, and the second positioning pin hole on the second end face of the transition plate corresponds to the pin hole on the first end face of the extension shaft, and the first connecting through hole on the second end face of the transition plate corresponds to the threaded hole on the first end face of the extension shaft. The second positioning pin is embedded in the second positioning pin hole, and the second fastening screw is pre-installed in the first connecting through hole to ensure that the first end face of the extension shaft is close to the second end face of the transition plate. After the extension shaft has completely cooled down, the second positioning pin is tightened and the second fastening screw is tightened. S5. Adjust the long shaft on a CNC lathe to ensure that the concentricity of the long shaft and the rotor is within 0.02mm. S6. Hoist the rotor with the extended shaft assembled and adjusted to the wheel groove milling machine. Connect the connecting flange at the second end of the extended shaft to the indexing plate of the wheel groove milling machine. Set a front hydrostatic bracket at the extended shaft position to support the front end of the rotor, and set a rear hydrostatic bracket at the rear journal of the rotor to support the rear end of the rotor.

2. The clamping method according to claim 1, characterized in that, There are two first positioning pin holes and six first countersunk holes.

3. The clamping method according to claim 1, characterized in that, There are two second positioning pin holes and four first connecting through holes.

4. The clamping method according to claim 1, characterized in that, In step S1, the step of "heating the assembly groove on the first end face of the transition plate until the diameter of the assembly groove meets the heat fitting requirements" specifically means: uniformly heating the assembly groove with a flame gun until the diameter of the assembly groove increases by 0.05-0.1mm.

5. The clamping method according to claim 1, characterized in that, In step S3, the step of "heating the assembly hole at the first end of the docking long shaft until the diameter of the assembly hole meets the requirements of the heat fitting" specifically means: uniformly heating the assembly hole at the first end of the docking long shaft with a flame gun until the diameter of the assembly hole increases by 0.05-0.1mm.

6. The clamping method according to claim 1, characterized in that, Along the radial direction of the indexing plate, four T-slots are provided on the indexing plate. The four T-slots are evenly distributed along the circumferential direction of the indexing plate. T-blocks are embedded in two mutually symmetrical T-slots. The T-blocks are provided with threaded holes, and connecting screws are provided in the threaded holes. In step S6, "connecting the connecting flange provided at the second end of the extension shaft to the indexing plate of the wheel groove milling machine" specifically involves: fitting a transmission pin sleeve in the through hole provided on the connecting flange, passing the connecting screw through the transmission pin sleeve, and putting a washer on the end of the connecting screw and screwing on a nut to completely tighten the connecting flange and the indexing plate.

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