Clamping method for machining turbine shaft mounting portion of turbine rotor

Abstract

The application discloses a clamping method for machining a turbine shaft mounting part of a turbine rotor, S1, connecting a connecting seat with a driving device and fixing an elastic chuck with a linear driver on the driving device; S2, a nose head of the turbine rotor is passed through a tightening cover and matched with the elastic chuck, the elastic chuck preliminarily clamps the nose head, and the rest of the turbine rotor is exposed outside the tightening cover; S3, the linear driver drives the elastic chuck to linearly feed; and S4, at least a part of the turbine shaft mounting part of the turbine rotor is located in or passes through a stepped hole, and when the rotor body and a stepped surface of the stepped hole form abutment, the linear driver stops linear feeding. The application can respectively obtain axial and radial positioning of both ends of the turbine rotor, and prevent the turbine rotor from jumping during cutting of the turbine shaft mounting part.

Description

Technical Field

[0001] This invention relates to the field of turbine rotor machining technology, and more specifically to a clamping method for machining the turbine shaft mounting portion on a turbine rotor. Background Technology

[0002] like Figure 1 As shown, the finished turbine consists of a turbine rotor and a turbine shaft B. Typically, after the turbine rotor is cast, it has a rotor body A, a turbine shaft mounting part C at one end of the rotor body A, and a nose D at the other end of the rotor body A. The turbine shaft mounting part C and the nose D protrude from the axial end face of the rotor body A. The turbine shaft mounting part C is annular, meaning it has a central hole E. One end of the turbine shaft B has a protrusion F, and a shoulder G is formed between the protrusion F and the turbine shaft B. During installation, the protrusion F is inserted into the central hole of the turbine shaft mounting part C, and the shoulder G mates with the axial end face of the turbine shaft mounting part C. The axial end face of the turbine shaft mounting part C is then welded to the shoulder G on the turbine shaft B, thus fixing the turbine rotor and the turbine shaft B into one unit.

[0003] Because the turbine is a high-speed rotating component, the assembly requirements for the turbine rotor and turbine shaft B are relatively high. Since the turbine rotor is a casting, the cast turbine shaft mounting portion C needs to be machined, especially its axial end face and center hole. However, because both the turbine shaft mounting portion C and the nose D are relatively short, existing clamping mechanisms such as three-jaw chucks cannot directly clamp them. Therefore, existing technologies typically use a three-jaw chuck to clamp the outer diameter of the rotor body A. Although the three-jaw chuck can clamp the outer circle or apply axial tension while clamping the outer circle, so that the axial end face of the rotor body A with the nose D forms abutment with the three-jaw chuck, the nose D and the clamped outer circle are basically located at the same end. When machining the turbine shaft mounting part C at the other end, the turbine shaft mounting part C will be subjected to radial cutting force, which will cause the turbine shaft mounting part C to run out, resulting in a decrease in machining accuracy. If the accuracy of the turbine shaft mounting part C itself cannot be guaranteed, the assembly accuracy of the turbine shaft mounting part C and the turbine shaft B cannot meet the corresponding requirements.

[0004] In addition, CN109986102 A discloses a clamping fixture for machining the center hole of the turbine shaft assembly nose. This clamping fixture is primarily used for machining the nose, and the nose is machined only after the turbine rotor and turbine shaft are assembled. During clamping, the turbine shaft needs to be inserted into the center hole on the chuck, and the initial positioning is achieved by the cooperation between the turbine shaft and the chuck. Obviously, when this clamping fixture is used to clamp the turbine rotor (the nose of the turbine rotor corresponds to the center hole on the chuck, while the turbine shaft mounting part is exposed outside the clamping fixture), it faces the same problem as the three-jaw chuck mentioned above, that is, only one end is axially positioned, which will cause the turbine rotor to run out of space during machining. Summary of the Invention

[0005] This invention provides a clamping method for machining the turbine shaft mounting portion on a turbine rotor. This invention enables the turbine rotor to be axially and radially positioned at both ends, preventing the turbine rotor from jumping during the cutting of the turbine shaft mounting portion.

[0006] The technical solutions to the above technical problems are as follows: A clamping method for machining the turbine shaft mounting portion on a turbine rotor includes the following steps: S1, connect the connecting seat to the drive device, and fix the elastic clamp to the linear driver on the drive device; S2, pass the nose of the turbine rotor through the tightening cover and engage with the elastic clamp. The elastic clamp forms an initial clamp on the nose, and the rest of the turbine rotor is exposed outside the tightening cover. S3, the linear actuator drives the elastic chuck to feed linearly, so that the conical surface of the elastic chuck engages with the conical hole of the tightening cover. Under the action of the linear actuator, the elastic chuck continues to feed linearly. The elastic chuck drives the turbine rotor, the tightening cover and the thrust seat fixed to the tightening cover to feed linearly towards the axial limiting assembly. With the cooperation of the elastic chuck, the tightening cover, the thrust seat and the elastic component, the elastic chuck further generates clamping force on the nose. S4, at least a portion of the turbine shaft mounting portion of the turbine rotor is located in or through the stepped hole, and when the rotor body abuts against the stepped surface of the stepped hole, the linear drive stops the linear feed.

[0007] By employing the above-mentioned solution, since the nose of one end of the turbine rotor is clamped by the elastic chuck, and one end of the turbine rotor abuts against the tightening cover, one end of the turbine rotor is axially limited and cannot move radially. For the other end of the turbine rotor, because the rotor body mates with the stepped hole (i.e., a portion of the rotor body's circumferential surface is clearance-fitted with the stepped hole), the other end of the turbine rotor cannot move radially. Furthermore, the axial end face of the rotor body abuts against the stepped surface of the stepped hole, preventing axial movement of the other end of the turbine rotor. When machining the turbine shaft mounting portion, under radial force, because both ends of the turbine rotor are axially and radially positioned respectively, the turbine rotor cannot exhibit radial runout. The beneficial effects of this invention compared to the prior art are: 1. The clamping is firm, meeting the product processing requirements, ensuring the product's perpendicularity and coaxiality, and is suitable for processing various types of turbine rotors.

[0008] 2. Replacing products is relatively simple and convenient.

[0009] 3. It has a simple structure, few parts, and good economic efficiency. Attached Figure Description

[0010] Figure 1 This is an exploded view of the finished turbine.

[0011] Figure 2 A cross-sectional view of the fixture for machining the turbine shaft mounting portion on the turbine rotor in this invention (in a clamping state for the product).

[0012] Figure 3 A partial structural diagram (non-clamping state) of the fixture used to machine the turbine shaft mounting part on the turbine rotor.

[0013] Figure 4 This is an assembly drawing of the sleeve, thrust seat, and elastic clamp.

[0014] Figure 5 This is a three-dimensional view of the sleeve.

[0015] Figure 6 This is a 3D view of the flexible clamp.

[0016] Figure 7 This is a structural diagram of another type of axial limiting component.

[0017] Labels in the attached diagram: Rotor body A, turbine shaft B, turbine shaft mounting part C, nose D, center hole E, protrusion F, shoulder G, connecting seat 1, through hole 1a, mounting hole 1b, sleeve 2, blind hole 2a, radial opening 2b, thrust seat 3, first through hole 3a, thrust seat body 3b, mounting seat 3c, elastic chuck 4, second connecting part 4a, clamping block 4b, insertion part 4c, tightening cover 5, second through hole 5a, elastic component 6, first connecting part 7, clearance space 7a, limiting part 8, stepped hole 8, quick-release clamping mechanism 9. Detailed Implementation

[0018] The present invention will now be described in detail with reference to the accompanying drawings.

[0019] like Figures 1 to 6 As shown, the fixture for machining the turbine shaft mounting portion on the turbine rotor of the present invention includes a connecting seat 1, a sleeve 2, a thrust seat 3, an elastic chuck 4, a tightening cover 5, an elastic component 6, and an axial limiting assembly. The following is a detailed description of each part and the relationship between them: like Figures 1 to 6 As shown, the connecting seat 1 preferably adopts a flange. The connecting seat 1 is provided with a through hole 1a and a mounting hole 1b. The linear actuator (not shown in the figure) passes through the through hole 1a. One end of the sleeve 2 is fixed to the connecting seat 1. The screw passes through the mounting hole 1b and is threadedly connected to the threaded hole provided on the sleeve 2, thereby fixing the sleeve 2 to the connecting seat 1.

[0020] like Figures 1 to 6 As shown, the thrust seat 3 mates with the inner hole of the sleeve 2, and the thrust seat 3 is provided with a first through hole 3a. In this embodiment, the thrust seat 3 includes a thrust seat body 3b and an assembly seat 3c. The first through hole 3a is provided on the thrust seat body 3b, and the assembly seat 3c is provided on the circumferential surface of the thrust seat body 3b. One end of the elastic member 6 mates with the assembly seat 3c.

[0021] like Figures 1 to 6 As shown, the elastic chuck 4 is used to clamp the nose D on the turbine rotor. The elastic chuck 4 cooperates with the first through hole 3a. One end of the elastic chuck 4 is tapered. The elastic chuck 4 includes a second connecting part 4a for connecting the linear actuator and a clamping part. The clamping part includes a plurality of clamping blocks 4b arranged circumferentially along the second connecting part 4a. One end of these clamping blocks 4b is fixed to the second connecting part 4a, and the other end of the clamping blocks 4b is a free end. The thickness of the clamping blocks 4b is less than the radius of the second connecting part 4a, so that a plug-in part 4c for the nose D to be inserted is formed between the plurality of clamping blocks 4b.

[0022] like Figures 1 to 6As shown, the tightening cover 5 is used to generate a radial tightening force on the elastic chuck 4 when it moves. The tightening cover 5 is provided with a second through hole 5a, at least a part of which is a conical hole. The tightening cover 5 is fixed to the other end of the thrust seat 3. In this embodiment, a part of the outer peripheral surface of the tightening cover 5 is a conical surface. The second through hole 5a is composed of a conical hole and a straight hole, and a limiting part is formed between the conical hole and the straight hole. The conical part of the elastic chuck 4 passes through the straight hole and engages with the conical hole. When the cylindrical section of the elastic chuck 4 abuts against the limiting part between the conical hole and the straight hole, the elastic chuck 4 cannot be further linearly fed relative to the tightening cover 5. At this time, the elastic chuck 4 transmits the feeding power to the tightening cover 5, so that the tightening cover 5 moves linearly along with the elastic chuck 4.

[0023] like Figures 1 to 6 As shown, the elastic component 6 generates elastic resistance to the thrust seat 3 when it moves. One end of the elastic component 6 engages with the thrust seat 3, and the other end engages with the sleeve 2. The elastic component 6 is a spring. The spring can be a helical spring or a gas spring. In this embodiment, a helical spring is preferred.

[0024] like Figures 1 to 6 As shown, in this embodiment, the sleeve 2 is provided with a blind hole 2a, and the other end of the elastic member 6 mates with the blind hole 2a. The inner wall surface of the sleeve 2 is provided with a radial opening 2b for mates with the thrust seat 3, and the radial opening 2b communicates with the blind hole 2a. A portion of the mounting base 3c mates with the radial opening 2b, and another portion of the mounting base 3c mates with the blind hole 2a.

[0025] like Figures 1 to 6 As shown, the mounting base 3c consists of a cylindrical section and a shank. One end of the shank is fixed to the thrust seat body 3b, and the other end is fixed to the cylindrical section. The shank is clearance-fitted with the radial opening 2b, and the cylindrical section is clearance-fitted with the blind hole 2a. The width of the shank is smaller than the outer diameter of the cylindrical section. Thus, the cylindrical section is confined within the blind hole 2a, allowing the mounting base 3c to move only along the axial direction of the blind hole 2a. The mounting base 3c cannot move circumferentially or radially along the sleeve 2.

[0026] like Figures 1 to 6 As shown, at least a portion of the axial limiting assembly surrounds the tightening cover 5. The axial limiting assembly includes a first connecting portion 7 and a limiting portion 8. One end of the first connecting portion 7 is fixed to the other end of the sleeve 2, and the limiting portion 8 is fixed to the other end of the first connecting portion 7. The limiting portion 8 is provided with a stepped hole 8a for engaging with the rotor body A of the turbine rotor.

[0027] like Figures 1 to 6As shown, when the rotor body A abuts against the stepped portion of the stepped hole 8a, the rotor body A cannot be further fed axially, and the thrust seat 3, elastic chuck 4, and tightening cover 5 also cannot be further fed axially. At this time, at least a part of the turbine shaft mounting part C is located in or passes through the stepped hole 8a, and the turbine shaft mounting part C reaches the predetermined machining position, so that the turbine shaft mounting part C can be machined by a cutting device.

[0028] like Figures 1 to 6 As shown, there are multiple first connecting parts 7, and a clearance space 7a is provided between two adjacent first connecting parts 7 for the turbine rotor to pass through. In this embodiment, there are two first connecting parts 7, and there are two clearance spaces 7a between the two first connecting parts 7. After the turbine rotor enters the axial limiting assembly through the clearance space 7a, the nose D of the turbine rotor is inserted into the insertion part 4c between the clamping blocks 4b.

[0029] The first connecting portion 7 with the above structure allows the first connecting portion 7 and the limiting portion to be integrally formed. Of course, if an integrally formed structure is not required, or if there is space 7a between different first connecting portions 7, the first connecting portion 7 and the limiting portion 8 can also adopt the following structure: like Figure 7 As shown, the first connecting part 7 is cylindrical. The first connecting part 7 and the limiting part 8 are hinged together, or the limiting part 8 is covered on the first connecting part 7. The first connecting part 7 and the limiting part 8 can be clamped together by a quick-release clamping mechanism 9. The quick-release clamping mechanism 9 includes a hinge seat, a screw, a clamping nut, and a clamping seat. The hinge seat is disposed on the outer peripheral surface of the first connecting part 7. One end of the screw is hinged to the hinge seat, and the other end of the screw is threaded to the clamping nut. The clamping seat is disposed on the peripheral surface of the limiting part 8. The clamping seat has an opening. After the screw engages with the opening on the clamping seat, the clamping nut is rotated to engage with the clamping seat, thereby clamping the limiting part 8.

[0030] like Figures 1 to 6 As shown, the clamping method for machining the turbine shaft mounting portion on the turbine rotor, using the fixture described in the above embodiment, includes the following steps: S1, connect the connecting seat 1 to the drive device, and fix the elastic chuck 4 to the linear actuator on the drive device. In this step, the drive device is a machine tool, and the linear actuator is a hydraulic cylinder or pneumatic cylinder mounted on the machine tool.

[0031] S2, the nose D of the turbine rotor is passed through the tightening cover 5 and engaged with the elastic clamp 4. The elastic clamp 4 forms an initial clamp on the nose D, and the rest of the turbine rotor is exposed outside the tightening cover 5. S3, the linear actuator drives the elastic chuck 4 to feed linearly, so that the conical surface of the elastic chuck 4 engages with the conical hole of the tightening cover 5. Under the action of the linear actuator, the elastic chuck 4 continues to feed linearly. The elastic chuck 4 drives the turbine rotor, the tightening cover 5 and the thrust seat 3 fixed to the tightening cover 5 to feed linearly towards the axial limiting assembly. With the cooperation of the elastic chuck 4, the tightening cover 5, the thrust seat 3 and the elastic component 6, the elastic chuck 4 further generates clamping force on the nose D.

[0032] In step S3, the process of the elastic chuck 4 further clamping the nose tip D is as follows: During the continued feeding process, the thrust seat 3 applies a force to the elastic component 6, and the elastic component 6 generates a reverse resistance against the thrust seat 3. The linear feed force output by the linear actuator is greater than the reverse resistance generated by the elastic component 6. This resistance is transmitted to the elastic chuck 4 through the tightening cover 5, and the tightening cover 5 generates a radial tightening force on the elastic chuck 4, causing the elastic chuck 4 to further clamp the nose tip D.

[0033] S4, at least a portion of the turbine shaft mounting portion C of the turbine rotor is located in or through the stepped hole 8a, and when the rotor body A abuts against the stepped surface of the stepped hole 8a, the linear drive stops the linear feed. A portion of the rotor body A is located inside the stepped hole 8a and its circumferential surface is clearance-fitted with the stepped hole 8a, and the axial end face of the rotor body A abuts against the stepped surface of the stepped hole 8a.

[0034] Because the nose D at one end of the turbine rotor is held by the elastic chuck 4, and one end of the turbine rotor abuts against the tightening cover 5, one end of the turbine rotor is axially limited and cannot move radially. As for the other end of the turbine rotor, because the rotor body A mates with the stepped hole 8a (i.e., a portion of the circumferential surface of the rotor body A is clearance-fitted with the stepped hole 8a), the other end of the turbine rotor cannot move radially. Furthermore, the axial end face of the rotor body A abuts against the stepped surface of the stepped hole 8a, preventing axial movement of the other end of the turbine rotor. When the turbine shaft mounting portion C is machined, under radial force, because both ends of the turbine rotor are axially and radially positioned respectively, the turbine rotor cannot exhibit radial runout.

[0035] Finally, it should be noted that the above embodiments are merely preferred embodiments used to illustrate the technical solutions of the invention, and are not intended to limit the invention or restrict its patent scope. Although the invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the invention. In addition, the direct or indirect application of the technical solutions of the invention to other related technical fields is also included within the patent protection scope of the invention.

Claims

1. A clamping method for machining the turbine shaft mounting portion on a turbine rotor, characterized in that, Includes the following steps: S1, connect the connecting seat (1) to the drive device, and fix the elastic clamp (4) to the linear driver on the drive device; S2, the nose (D) of the turbine rotor is passed through the tightening cover (5) and engaged with the elastic clamp (4). The elastic clamp (4) forms an initial clamp on the nose (D), and the rest of the turbine rotor is exposed outside the tightening cover (5). S3, the linear actuator drives the elastic chuck (4) to feed linearly, so that the conical surface of the elastic chuck (4) engages with the conical hole of the tightening cover (5). Under the action of the linear actuator, the elastic chuck (4) continues to feed linearly. The elastic chuck (4) drives the turbine rotor, the tightening cover (5) and the thrust seat (3) fixed to the tightening cover (5) to feed linearly toward the axial limiting assembly. With the cooperation of the elastic chuck (4), the tightening cover (5), the thrust seat (3) and the elastic component (6), the elastic chuck (4) further generates clamping force on the nose (D). S4, at least a portion of the turbine shaft mounting portion (C) of the turbine rotor is located in or through the stepped hole (8a), and when the rotor body (A) abuts against the stepped surface of the stepped hole (8a), the linear drive stops linear feed.

2. The clamping method for machining the turbine shaft mounting portion on the turbine rotor according to claim 1, characterized in that, In step S1, the driving device is a machine tool, and the linear drive is a hydraulic cylinder or pneumatic cylinder installed on the machine tool.

3. The clamping method for machining the turbine shaft mounting portion on the turbine rotor according to claim 1, characterized in that, In step S3, the process of the elastic chuck (4) further clamping the nose (D) is as follows: During the continued feeding process, the push seat (3) applies a force to the elastic component (6), and the elastic component (6) generates a reverse resistance to the push seat (3). This resistance is transmitted to the elastic chuck (4) through the tightening cover (5), and the tightening cover (5) generates a radial tightening force on the elastic chuck (4), so that the elastic chuck (4) further clamps the nose (D).

4. The clamping method for machining the turbine shaft mounting portion on the turbine rotor according to claim 3, characterized in that, The linear feed force output by the linear actuator is greater than the reverse resistance generated by the elastic component (6).

5. The clamping method for machining the turbine shaft mounting portion on the turbine rotor according to claim 1, characterized in that, A portion of the rotor body (A) is located inside the stepped hole (8a) and its circumferential surface is in clearance fit with the stepped hole (8a). The axial end face of the rotor body (A) abuts against the stepped surface of the stepped hole (8a).

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