Gas turbine and turbine rotor connecting structure and fastening nut thereof

Abstract

The utility model discloses a gas turbine, a turbine rotor connecting structure of the gas turbine and a fastening nut, and relates to the technical field of gas turbines. The fastening nut is applied to the turbine rotor, the turbine rotor comprises a center shaft and a stay bolt, an assembly gap is formed between the center shaft and the stay bolt, an arc-shaped groove is formed in the first end of the fastening nut, and the width of the arc-shaped groove is larger than or equal to that of the assembly gap. The arc-shaped groove is formed in the fastening nut, so that the end face of the fastening nut can completely make contact with the end face of the center hole, and stress concentration cannot be formed on the end face of the fastening nut. When the fastening nut is used, the stress borne by the fastening nut can be evenly dispersed to the arc-shaped groove. Compared with a certain point on the end face of the fastening nut for bearing all stresses, the whole arc-shaped groove bears all stresses, so that the phenomenon of stress concentration can be effectively avoided.

Description

Technical Field

[0001] The present application relates to the technical field of gas turbines, and in particular to a gas turbine and a turbine rotor connection structure and a fastening nut thereof. Background Art

[0002] As gas turbines are evolving toward higher compression ratios and higher turbine inlet temperatures, existing gas turbine rotors operate in extremely demanding environments. They must withstand high temperature and centrifugal loads, as well as the thermal cycling of temperature increases and decreases during startup and shutdown. Consequently, the life of a gas turbine rotor is a key factor limiting its reliability and longevity. The damage tolerance fatigue life calculation method for a gas turbine rotor is based on fatigue sources such as microcracks or defects in various turbine components, as well as thermal loads and stress conditions. If the turbine rotor's structural design leads to stress concentration, these fatigue sources, such as microcracks, will develop during operation and gradually expand during startup and shutdown, eventually causing the cracks in the turbine rotor to exceed their service limits and fail. Therefore, avoiding stress concentrations caused by improper design in the turbine rotor's structural design is crucial for high reliability and long life of gas turbines.

[0003] In the turbine rotor connection structure of a certain type of gas turbine, such as Figure 1 As shown in the figure, the center shaft and the compressor shaft (not shown) are fastened together by tie bolts and fastening nuts. The tie bolts are set in the center holes of the turbine shaft and the compressor shaft. The tight connection between the two shafts is ensured by controlling the elongation or tightening torque of the tie bolts. In order to ensure that the tie bolts can pass through the center hole smoothly, a certain assembly allowance is formed between the tie bolts and the center hole during design, that is, Figure 1 As shown in the figure, after the tie rod bolt is assembled, an assembly gap will be formed with the central axis. The force acting on the tightening nut and tie rod bolt is mainly axial force, as shown in the figure. Figure 1 As shown in the figure, since the end face of the fastening nut is partially in contact with the end face of the center hole of the center shaft, Figure 1 As shown in FIG, the end face of the fastening nut is located at the critical point where it contacts the end face of the center hole, which will cause stress concentration. In other words, the end face of the fastening nut is located at the critical point where it contacts the end face of the center hole, which has the risk of generating a small fatigue source. Utility Model Content

[0004] The purpose of the present application is to provide a gas turbine and its turbine rotor connection structure and fastening nut to solve the technical problem that stress concentration is easily generated in the fastening nut of the turbine rotor connection structure of the existing gas turbine.

[0005] To achieve the above objectives, this application provides the following technical solutions:

[0006] In the first aspect, the present application proposes a technical solution for a fastening nut, which is applied to a turbine rotor, wherein the turbine rotor includes a central shaft and a pull rod bolt, an assembly gap is provided between the central shaft and the pull rod bolt, and an arc groove is provided at the first end of the fastening nut, and the width of the arc groove is greater than or equal to the width of the assembly gap.

[0007] As a specific technical solution in the present application, the width of the arc-shaped groove is less than or equal to 1 / 2 times the wall thickness of the fastening nut.

[0008] As a specific technical solution in the present application, a plurality of first clamping protrusions are provided at the second end of the fastening nut, and the first clamping protrusions are distributed around the circumference of the fastening nut, and first clamping grooves are formed between adjacent first clamping protrusions.

[0009] As a specific technical solution in the present application, a first inclined surface is provided at one end of the first clamping protrusion away from the fastening nut, and the distance between the first inclined surface and the second end of the fastening nut decreases along the circumference of the fastening nut.

[0010] In a second aspect, the present application proposes a technical solution for a turbine rotor connection structure, the turbine rotor connection structure comprising:

[0011] tie rod bolts;

[0012] A fastening nut as described in any one of the first aspects; the fastening nut can be threadedly connected to the first end of the pull rod bolt.

[0013] As a specific technical solution in the present application, a locking nut is also included; the locking nut is arranged at the first end of the pull rod bolt, and is used to limit the displacement of the fastening nut along the axial direction of the pull rod bolt.

[0014] As a specific technical solution in this application, the locking nut can be threadedly connected to the first end of the pull rod bolt; a plastic ring is provided at one end of the locking nut; a locking groove is provided at the first end of the pull rod bolt, and the locking groove extends along the axial direction of the pull rod bolt.

[0015] As a specific technical solution in the present application, the turbine rotor connection structure includes a fastening nut as described in the first aspect; a threaded column is provided at the first end of the pull rod bolt, and the thread on the threaded column is opposite to the thread of the pull rod bolt; the locking nut can be threadedly connected to the threaded column; a plurality of second clamping protrusions are provided at one end of the locking nut close to the fastening nut, and a second clamping groove is provided between adjacent second clamping protrusions; the first clamping groove is adapted to the second clamping protrusion; the second clamping groove is adapted to the first clamping protrusion; a second inclined surface is provided at one end of the second clamping protrusion away from the locking nut, and the second inclined surface is parallel to the first inclined surface; the first clamping protrusion and / or the second clamping protrusion can form elastic deformation.

[0016] As a specific technical solution in the present application, the fastening nut and the first clamping protrusion are an integrally formed structure; the locking nut and the second clamping protrusion are an integrally formed structure.

[0017] In a third aspect, the present application proposes a gas turbine comprising a fastening nut as described in any one of the first aspects, or a turbine rotor connection structure as described in any one of the second aspects.

[0018] Compared with the prior art, the present invention has the following advantages:

[0019] This application provides an arcuate groove on the fastening nut, allowing the end face of the fastening nut to fully contact the end face of the center hole, meaning that stress concentration will not form on the end face of the fastening nut. When the fastening nut is in use, the stress it bears will be evenly distributed to the arcuate groove. Compared to a single point on the end face of the fastening nut bearing all the stress, the entire arcuate groove bears all the stress, effectively avoiding the occurrence of stress concentration. If the fastening nut does not generate stress concentration, the risk of the fastening nut generating a small fatigue source can also be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a cross-sectional schematic diagram of a turbine rotor connection structure in the prior art;

[0021] Figure 2 A three-dimensional schematic diagram of a fastening nut proposed in an embodiment of the present application;

[0022] Figure 3 A schematic cross-sectional view of a fastening nut proposed in an embodiment of the present application;

[0023] Figure 4 A schematic cross-sectional view of a turbine rotor connection structure proposed in an embodiment of the present application;

[0024] Figure 5 for Figure 4Enlarged view of part A;

[0025] Figure 6 This is a schematic cross-sectional view of another turbine rotor connection structure proposed in an embodiment of the present application;

[0026] Figure 7 This is a schematic diagram of a connection between a locking nut and a tie rod bolt proposed in an embodiment of the present application;

[0027] Figure 8 A three-dimensional schematic diagram of a turbine rotor connection structure proposed in an embodiment of the present application;

[0028] Figure 9 This is a schematic cross-sectional view of another turbine rotor connection structure proposed in an embodiment of the present application.

[0029] In the figure: 1. Central axis; 2. Pull rod bolt; 21. Locking groove; 22. Threaded column; 3. Fastening nut; 31. Stress point; 32. Arc groove; 33. First clamping protrusion; 34. First clamping groove; 35. First inclined surface; 4. Assembly gap; 5. Locking nut; 51. Plastic ring; 52. Second clamping protrusion; 53. Second clamping groove; 54. Second inclined surface. DETAILED DESCRIPTION

[0030] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0031] It should be noted that, in the description of this application, the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as a limitation on this application.

[0032] Furthermore, it should be understood that for the sake of ease of description, the sizes of the various components shown in the drawings are not drawn according to actual proportions. For example, the thickness or width of certain layers may be exaggerated relative to other layers.

[0033] It should be noted that like numbers and letters represent similar items in the following figures, so once an item is defined or described in one figure, it will not need to be further discussed and described in detail in the description of the subsequent figures.

[0034] Before understanding the embodiments of the present application, it should be noted that in order to simplify the drawings in the present application so that technicians in this field can clearly understand the specific structures of various parts proposed in the embodiments of the present application, the threads of all parts (for example: the pull rod bolt 2, fastening nut 3, locking nut 5 and threaded column 22 mentioned below) are omitted in the drawings of the present application.

[0035] In order to solve the technical problem that the end face of the fastening nut and the end face of the center hole in the prior art are partially in contact with each other, which will cause stress concentration, the present application proposes a fastening nut 3, which is applied to a turbine rotor. The turbine rotor includes a central shaft 1 and a tie rod bolt 2. An assembly gap 4 is provided between the central shaft 1 and the tie rod bolt 2. The first end of the fastening nut 3 is provided with an arc groove 32. The width of the arc groove 32 (that is, as shown in FIG. Figure 3 The width S2 shown is greater than or equal to the width of the assembly gap 4 (ie, Figure 4 Width S3 shown).

[0036] It should be clear that if Figure 3 As shown, since the width of the arcuate groove 32 is greater than the width of the assembly gap 4, the end face of the fastening nut 3 (i.e., the end face of the first end of the fastening nut 3) can be in full contact with the end face of the center hole, i.e., no single stress point 31 is formed on the end face of the fastening nut 3. Figure 5 As shown, due to the arrangement of the arc groove 32, multiple stress points 31 are formed on the arc groove 32. That is, in the embodiment of the present application, the stress borne by the fastening nut 3 is evenly distributed to the arc groove 32 when in use (i.e., Figure 5 The arcuate groove 32 shown in FIG. 1 is a schematic diagram of a fastening nut 3 having a plurality of stress points 31 disposed on the fastening nut 3. In contrast to a single point on the end face of the fastening nut 3 bearing all stress, the entire arcuate groove 32 bears all stress, effectively avoiding stress concentration. Avoiding stress concentration in the fastening nut 3 also reduces the risk of micro fatigue sources in the fastening nut 3.

[0037] In order to avoid stress concentration on the end surface of the central hole, in one embodiment of the present application, the width of the arc-shaped groove 32 may be equal to the width of the assembly gap 4 .

[0038] It should be clear that the durability of the fastening nut 3 is directly proportional to its wall thickness. That is to say, the thicker the wall thickness of the fastening nut 3, the better the durability of the fastening nut 3; the thinner the wall thickness of the fastening nut 3, the worse the durability of the fastening nut 3. It should be noted that the wider the width of the arc groove 32, the thinner the corresponding wall thickness of the fastening nut 3; if the width of the arc groove 32 is narrower, stress concentration may still occur at the arc groove 32. After a lot of experimental research by the inventor, in order to ensure that the fastening nut 3 has a certain durability and that stress concentration does not occur at the arc groove 32, in one embodiment of the present application, the width of the arc groove 32 may be greater than or equal to 1 / 3 times the wall thickness of the fastening nut 3 (that is, as Figure 3 The thickness S1) shown is less than or equal to 1 / 2 times the wall thickness of the fastening nut 3.

[0039] In the embodiment of the present application, there is no restriction on the shape and structure of the fastening nut 3. For example, the fastening nut 3 can be a nut with a cylindrical shape or a nut with a hexagonal shape (the same is true for the locking nut 5 below, which will not be described in detail later). It should be noted that, if Figure 1 and Figure 4 As shown, in the application scenario of the turbine rotor connection structure proposed in this application, the assembly space of the fastening nut 3 is limited. In order to facilitate the rotation of the fastening nut 3, in one embodiment of the present application, as shown in FIG. Figure 2 and Figure 3 As shown, the second end of the fastening nut 3 is provided with a plurality of first engaging protrusions 33. The first engaging protrusions 33 are distributed around the circumference of the fastening nut 3, and first engaging grooves 34 are formed between adjacent first engaging protrusions 33. During use, the first engaging grooves 34 can be engaged with a tool, and the fastening nut 3 can then be rotated by the tool.

[0040] It should be understood that the fastening nut proposed in the embodiment of the present application is provided with an arcuate groove so that the end face of the fastening nut can be in full contact with the end face of the center hole, that is, the end face of the fastening nut will not form stress concentration. When the fastening nut is in use, the stress it bears will be evenly distributed to the arcuate groove. Compared with a certain point on the end face of the fastening nut bearing all the stress, the entire arcuate groove bearing all the stress can effectively avoid the occurrence of stress concentration. If the fastening nut does not generate stress concentration, the risk of the fastening nut generating a small fatigue source can also be reduced.

[0041] After introducing the fastening nut proposed in the embodiment of the present application, the following describes a turbine rotor connection structure proposed in the present application. The turbine rotor connection structure includes a tie rod bolt 2 and a fastening nut 3 proposed in any one of the above embodiments. Figure 4 or Figure 5As shown, the fastening nut 3 can be threadedly connected to the first end of the pull rod bolt 2.

[0042] It should be understood that the fastening nut proposed in the embodiment of the present application is provided with an arcuate groove so that the end face of the fastening nut can be in full contact with the end face of the center hole, that is, the end face of the fastening nut will not form stress concentration. When the fastening nut is in use, the stress it bears will be evenly distributed to the arcuate groove. Compared with a certain point on the end face of the fastening nut bearing all the stress, the entire arcuate groove bearing all the stress can effectively avoid the occurrence of stress concentration. If the fastening nut does not generate stress concentration, the risk of the fastening nut generating a small fatigue source can also be reduced.

[0043] In order to prevent the fastening nut from loosening due to vibration during long-term use, that is, losing the fastening effect on the central shaft 1 and the compressor shaft (not shown in the figure), in one embodiment of the present application, the turbine rotor connection structure further includes a locking nut 5. The locking nut 5 is provided at the first end of the tie rod bolt 2 and is used to limit the displacement of the fastening nut 3 along the axial direction of the tie rod bolt 2.

[0044] In the embodiment of the present application, the locking nut 5 can be any nut that can limit the fastening nut 3 from being displaced axially along the pull rod bolt 2. For example, the locking nut 5 can be as shown in the following two embodiments.

[0045] Example 1 of locking nut

[0046] In this embodiment, if Figure 7 As shown, the locking nut 5 can be threadedly connected to the first end of the pull rod bolt 2. One end of the locking nut 5 is provided with a plastic ring 51. The first end of the pull rod bolt 2 is provided with a locking groove 21, which extends along the axial direction of the pull rod bolt 2.

[0047] During use, first rotate the fastening nut 3 to a preset position on the tie bolt 2, then rotate the locking nut 5 to a preset position on the tie bolt 2, and then pinch the plastic ring 51 into the locking groove 21 on the tie bolt 2. It is easy to understand that if the plastic ring 51 is pinched into the locking groove 21, the locking nut 5 cannot rotate due to the restraining effect of the plastic ring 51. If the locking nut 5 cannot rotate, the locking nut 5 cannot move axially along the tie bolt 2. If the locking nut 5 cannot move axially along the tie bolt 2, the locking nut 5 can limit the axial movement of the fastening nut 3 along the tie bolt 2.

[0048] In the embodiment of the present application, the plastic ring 51 may be any ring that can produce plastic deformation. For example, the plastic ring 51 may be a metal ring or a plastic ring.

[0049] Example 2 of Locking Nut

[0050] In this embodiment, if Figure 8 As shown, the first end of the tie bolt 2 is provided with a threaded column 22, the threads of which are opposite to those of the tie bolt 2. The lock nut 5 can be threadedly connected to the threaded column 22. The end of the first engaging protrusion 33 away from the fastening nut 3 is provided with a first inclined surface 35, the distance between the first inclined surface 35 and the second end of the fastening nut 3 decreasing along the circumference of the fastening nut 3. The end of the lock nut 5 near the fastening nut 3 is provided with multiple second engaging protrusions 52, and second engaging grooves 53 are provided between adjacent second engaging protrusions 52. The end of the second engaging protrusion 52 away from the tie bolt 5 is provided with a second inclined surface 54, which is parallel to the first inclined surface 35. The first engaging groove 34 is adapted to fit the second engaging protrusion 52, and the second engaging groove 53 is adapted to fit the first engaging protrusion 33. The first engaging protrusion 33 and / or the second engaging protrusion 52 are capable of elastic deformation.

[0051] In this embodiment, the first engaging groove 34 and the second engaging protrusion 52 are adapted to each other, meaning that the second engaging protrusion 52 can be engaged with the first engaging groove 34, and after the second engaging protrusion 52 is engaged with the first engaging groove 34, the locking nut 5 cannot rotate freely due to the restraining action of the first engaging groove 34 and the second engaging protrusion 52. The second engaging groove 53 and the first engaging protrusion 33 are adapted to each other, meaning that the first engaging protrusion 33 can be engaged with the second engaging groove 53, and after the first engaging protrusion 33 is engaged with the second engaging groove 53, the fastening nut 3 cannot rotate freely due to the restraining action of the second engaging groove 53 and the first engaging protrusion 33.

[0052] In this embodiment, it is assumed that the fastening nut 3 is rotated forward to tighten the central shaft 1 and the compressor shaft. When in use, the fastening nut 3 is first rotated forward to the preset position on the tie rod bolt 2, and then the locking nut 5 is rotated reversely to the threaded column 22 until the first inclined surface 35 and the second inclined surface 54 are in contact. Further, the locking nut 5 is rotated forcefully. Since the first clamping protrusion 33 and / or the second clamping protrusion 52 can form elastic deformation, Figure 8 As shown, the first engaging protrusion 33 can be engaged with the second engaging groove 53; the second engaging protrusion 52 can be engaged with the first engaging groove 34. As can be seen from the above, if the first engaging protrusion 33 is engaged with the second engaging groove 53, and the second engaging protrusion 52 is engaged with the first engaging groove 34, the fastening nut 3 will not be able to rotate in the reverse direction, and the locking nut 5 will not be able to rotate in the forward direction. If the fastening nut 3 cannot rotate in the reverse direction, then Figure 9 As shown, the fastening nut 3 is restricted between the locking nut 5 and the central shaft 1 , that is, the fastening nut 3 cannot generate axial displacement along the pull rod bolt 2 .

[0053] In the embodiments of the present application, forward rotation can be either clockwise or counterclockwise. It is readily understood that in this embodiment, reverse rotation is rotation in the opposite direction of forward rotation. For example, if forward rotation is clockwise, reverse rotation is counterclockwise; if forward rotation is counterclockwise, reverse rotation is clockwise.

[0054] It should be noted that in the embodiment of the present application, if it is necessary to remove the fastening nut 3 and the locking nut 5, a sufficiently large torque is applied to the locking nut 5 to destroy the clamping structure between the fastening nut 3 and the locking nut 5. In other words, in the embodiment of the present application, the clamping force formed between the fastening nut 3 and the locking nut 5 can be set according to actual needs, so that the fastening nut 3 will not be easily loosened, and the clamping structure between the fastening nut 3 and the locking nut 5 will be easily destroyed later.

[0055] In an embodiment of the present application, the first engaging protrusion 33 can be welded or bonded to the fastening nut 3. To ensure the connection strength between the fastening nut 3 and the first engaging protrusion 33, in one embodiment of the present application, the fastening nut 3 and the first engaging protrusion 33 can be integrally formed. For similar reasons, the locking nut 5 and the second engaging protrusion 52 can also be integrally formed.

[0056] After introducing the turbine rotor connection structure proposed in the embodiments of the present application, the following introduces a gas turbine proposed in the present application, which includes a fastening nut proposed in any one of the above embodiments, or includes a turbine rotor connection structure proposed in any one of the above embodiments.

[0057] It should be understood that the gas turbine proposed in the embodiment of the present application has an internal fastening nut that is provided with an arcuate groove so that the end face of the fastening nut can be in full contact with the end face of the center hole, that is, the end face of the fastening nut will not form stress concentration. When the fastening nut is in use, the stress it bears will be evenly distributed to the arcuate groove. Compared with a certain point on the end face of the fastening nut bearing all the stress, the entire arcuate groove bearing all the stress can effectively avoid the occurrence of stress concentration. If the fastening nut does not generate stress concentration, the risk of the fastening nut generating a small fatigue source can also be reduced.

[0058] Although the embodiments of the present application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations may be made to these embodiments without departing from the principles and spirit of the present application, and the scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A fastening nut (3) applied to a turbine rotor, the turbine rotor comprising a central shaft (1) and a tie rod bolt (2), an assembly gap (4) being provided between the central shaft (1) and the tie rod bolt (2), characterized in that: The first end of the fastening nut (3) is provided with an arc-shaped groove (32), and the width of the arc-shaped groove (32) is greater than or equal to the width of the assembly gap (4).

2. The fastening nut (3) according to claim 1, characterized in that The width of the arc-shaped groove (32) is less than or equal to 1 / 2 times the wall thickness of the fastening nut (3).

3. The fastening nut (3) according to claim 1 or 2, characterized in that: The second end of the fastening nut (3) is provided with a plurality of first clamping protrusions (33), each of which is distributed around the circumference of the fastening nut (3), and a first clamping groove (34) is formed between adjacent first clamping protrusions (33).

4. The fastening nut (3) according to claim 3, characterized in that A first inclined surface (35) is provided at one end of the first clamping protrusion (33) away from the fastening nut (3), and the distance between the first inclined surface (35) and the second end of the fastening nut (3) decreases along the circumference of the fastening nut (3).

5. A turbine rotor connection structure, characterized in that: include: Tie rod bolt (2); The fastening nut (3) according to any one of claims 1 to 4; the fastening nut (3) can be threadedly connected to the first end of the pull rod bolt (2).

6. The turbine rotor connection structure according to claim 5, characterized in that: It also includes a locking nut (5); the locking nut (5) is arranged at the first end of the pull rod bolt (2) and is used to limit the displacement of the fastening nut (3) along the axial direction of the pull rod bolt (2).

7. The turbine rotor connection structure according to claim 6, characterized in that: The locking nut (5) can be threadedly connected to the first end of the pull rod bolt (2); one end of the locking nut (5) is provided with a plastic ring (51); the first end of the pull rod bolt (2) is provided with a locking groove (21), and the locking groove (21) extends along the axial direction of the pull rod bolt (2).

8. The turbine rotor connection structure according to claim 6, characterized in that: The turbine rotor connection structure includes the fastening nut (3) as described in claim 4; the first end of the pull rod bolt (2) is provided with a threaded column (22), and the thread on the threaded column (22) is opposite to the thread of the pull rod bolt (2); the locking nut (5) can be threadedly connected to the threaded column (22); the locking nut (5) is provided with a plurality of second clamping protrusions (52) at one end close to the fastening nut (3), and a second clamping groove (53) is provided between adjacent second clamping protrusions (52); the first clamping groove (34) is adapted to the second clamping protrusion (52); the second clamping groove (53) is adapted to the first clamping protrusion (33); the second clamping protrusion (52) is provided with a second inclined surface (54) at one end away from the locking nut (5), and the second inclined surface (54) is parallel to the first inclined surface (35); the first clamping protrusion (33) and / or the second clamping protrusion (52) can form elastic deformation.

9. The turbine rotor connection structure according to claim 8, characterized in that: The fastening nut (3) and the first clamping protrusion (33) are an integrally formed structure; the locking nut (5) and the second clamping protrusion (52) are an integrally formed structure.

10. A gas turbine, characterized in that: It comprises the fastening nut (3) according to any one of claims 1 to 4, or comprises the turbine rotor connection structure according to any one of claims 5 to 9.

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