JP2010112316A - Rotor for gas turbine, and gas turbine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To increase reliability by reducing stress applied to a fastening bolt, in a rotor for a gas turbine and the gas turbine. <P>SOLUTION: This rotor for the gas turbine is so configured that a plurality of rotor disks 32 is axially arranged, and a spindle bolt 33 is passed through the plurality of rotor disks 32 and fastened by screwing a nut 34 around a thread 41. The spindle bolt 33 is formed with: a threading neck portion 42 provided adjacent to the thread 41 and having smaller diameter than the thread 41; a stress concentration reducing portion 43 provided adjacent to the neck portion 42 and having smaller diameter than the through-hole 32a of each rotor disk 32; and a stress receiving portion 44 fitted into the through-hole 32a of each rotor disk 32. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  For example, in a gas turbine in which fuel is supplied to compressed high-temperature and high-pressure air and burned, and the generated combustion gas is supplied to a turbine to obtain rotational power, a plurality of rotor disks are bolted. The present invention relates to a gas turbine rotor and a gas turbine.

  For example, a gas turbine is composed of a compressor, a combustor, and a turbine. The air taken in from the air intake port is compressed by the compressor to become high-temperature / high-pressure compressed air. Fuel is supplied to the compressed air and burned, and high-temperature and high-pressure combustion gas drives a turbine and a generator connected to the turbine. In this case, the turbine is configured by alternately arranging a plurality of stationary blades and moving blades in the vehicle interior, and rotationally drives an output shaft connected to the generator by driving the moving blades with combustion gas. ing. The combustion gas that has driven the turbine is converted to static pressure by the diffuser in the exhaust casing and then released to the atmosphere.

  In the gas turbine compressor configured as described above, the rotor for the gas turbine includes a plurality of rotor disks each having rotor blades arranged on the outer peripheral portion in the direction of the rotation axis of the compressor, and bolts by spindle bolts. It is constructed by fastening. That is, with respect to the plurality of arranged rotor disks, the spindle bolt passes through a position shifted in the radial direction from the rotor center, and a nut is screwed to each end portion of the spindle bolt, so that the plurality of rotor disks are spindles. Fastened so as to be clamped by bolts and nuts. In this case, the plurality of rotor disks are fastened by spindle bolts and nuts at a plurality of positions in the circumferential direction.

  As a spindle bolt mounting structure of a compressor having such a configuration, there is one described in Patent Document 1 below.

JP 2002-005084 A

  As described above, in a rotor for a gas turbine in which a plurality of rotor disks having moving blades are overlapped and fastened by a spindle bolt, the load of the rotor disk and the spindle bolt acts on the spindle bolt when the rotor rotates. The spindle bolt is deformed so that the intermediate portion is bent downward. Then, as the rotor rotates, the screw bolt formed at the axial end of the spindle bolt is repeatedly subjected to compressive stress and tensile stress, so that fretting fatigue is likely to occur and the life may be shortened. is there.

  The present invention solves the above-described problems, and an object of the present invention is to provide a gas turbine rotor and a gas turbine that improve the reliability by reducing the stress acting on the fastening bolt.

  In order to achieve the above object, a rotor for a gas turbine according to the invention of claim 1 is characterized in that a plurality of rotor disks having moving blades on the outer peripheral portion are arranged in the axial direction of the rotor rotating shaft, and fastening bolts In the rotor for a gas turbine, which passes through the rotor disk and is fastened by screwing a nut to a screw part formed at an end of the fastening bolt, the fastening bolt is adjacent to the screw part. A neck portion for threading with a smaller diameter, a stress concentration reducing portion smaller in diameter than the through hole of the rotor disk adjacent to the neck portion, and a stress receiving portion that fits into the through hole of the rotor disk It is characterized by that.

  In the gas turbine rotor according to a second aspect of the present invention, the through hole of the rotor disk has the threaded portion and the neck portion located on one side in the axial direction and the stress receiving portion located on the other side in the axial direction. The stress concentration reducing portion is located in the middle portion in the axial direction.

  In the rotor for a gas turbine according to a third aspect of the present invention, the neck portion and the stress concentration reducing portion have the same diameter, and are smaller in diameter than the through hole of the rotor disk.

  The gas turbine rotor according to a fourth aspect of the invention is characterized in that the stress concentration reducing portion extends from the neck portion beyond an intermediate position in the axial direction of the through hole of the rotor disk.

  A gas turbine according to a fifth aspect of the present invention is the gas turbine, wherein the compressed air compressed by the compressor is supplied with fuel by a combustor and burned, and the generated combustion gas is supplied to the turbine to obtain rotational power. In the rotor of the machine, a plurality of rotor disks having rotor blades on the outer periphery are arranged in the axial direction of the rotor rotation shaft, and fastening bolts pass through the plurality of rotor disks and are formed at end portions of the fastening bolts. The fastening bolt is fastened by screwing a nut into the screw portion, and the fastening bolt is adjacent to the screw portion, and has a neck portion for screw processing having a smaller diameter than the screw portion, and the rotor disk is adjacent to the neck portion. A stress concentration reducing portion having a diameter smaller than that of the through hole and a stress receiving portion that fits into the through hole of the rotor disk.

  According to the gas turbine rotor of the first aspect of the present invention, the plurality of rotor disks are arranged in the axial direction, the fastening bolts penetrate the plurality of rotor disks, and the nuts are screwed together to be fastened. The fastening bolt has a neck portion for threading smaller in diameter than the screw portion adjacent to the screw portion, and a stress concentration reducing portion smaller in diameter than the through hole of the rotor disk adjacent to the neck portion, A stress receiving portion that fits into the through hole of the rotor disk is provided. Therefore, when the rotor rotates, the fastening bolt is bent and deformed by the weight of the rotor disk and the fastening bolt, and a fluctuating stress acts on the contact portion between the fastening bolt and the rotor disk. Stress is received at the receiving portion, the response of the stress is slowed, the stress acting on the fastening bolt is reduced, and the reliability can be improved.

  According to the gas turbine rotor of the invention of claim 2, in the through hole of the rotor disk, the screw portion and the neck portion are located on one side in the axial direction, and the stress receiving portion is located on the other side in the axial direction, Since the stress concentration reducing portion is located in the axial intermediate portion, the stress concentration in the vicinity of the screw portion of the fastening bolt can be reduced by providing the stress concentration reducing portion in the axial intermediate portion of the through hole.

  According to the gas turbine rotor of the third aspect of the present invention, the neck portion and the stress concentration reducing portion have the same diameter, and the diameter is smaller than the through hole of the rotor disk. Therefore, the neck portion and the stress concentration reducing portion have the same diameter. Thus, the workability of the fastening bolt can be facilitated and the workability can be improved.

  According to the gas turbine rotor of the fourth aspect of the invention, the stress concentration reducing portion extends from the neck portion beyond the intermediate position in the axial direction in the through hole of the rotor disk. Stress is received at the stress receiving portion located away from the screw portion, and stress concentration can be reduced.

  According to the gas turbine of the fifth aspect of the present invention, the plurality of rotor disks are arranged in the axial direction, the fastening bolts penetrate the plurality of rotor disks, and the nuts are screwed into the threaded portions to be compressed. The machine rotor is configured, and the fastening bolt has a neck portion for threading smaller in diameter than the screw portion adjacent to the screw portion, and a stress concentration reducing portion smaller in diameter than the through hole of the rotor disk adjacent to the neck portion, A stress receiving portion that fits into the through hole of the rotor disk is provided. Therefore, when the compressor rotor is rotated, the fastening bolt is bent and deformed due to the weight of the rotor disk and the fastening bolt, and a fluctuating stress acts on the contact portion between the fastening bolt and the rotor disk. As a result, stress is received at the stress receiving portion, the response of the stress is slowed down, the stress acting on the fastening bolt is reduced, and the reliability can be improved.

  Exemplary embodiments of a gas turbine rotor and a gas turbine according to the present invention will be described below in detail with reference to the accompanying drawings. In addition, this invention is not limited by this Example.

  1 is a cross-sectional view showing a main part of a compressor rotor as a gas turbine rotor according to a first embodiment of the present invention, FIG. 2 is an enlarged view showing an end portion of a spindle bolt, and FIG. FIG. 4 is a cross-sectional view illustrating a gas turbine rotor according to the first embodiment.

  As shown in FIG. 3, the gas turbine according to the first embodiment includes a compressor 11, a combustor (gas turbine combustor) 12, a turbine 13, and an exhaust chamber 14, and a generator (not shown) is connected to the turbine 13. ing. The compressor 11 has an air intake port 15 for taking in air, a plurality of stationary blades 17 and moving blades 18 are alternately arranged in a compressor casing 16, and a bleed manifold 19 is provided on the outside thereof. ing. The combustor 12 is combustible by supplying fuel to the compressed air compressed by the compressor 11 and igniting it with a burner. In the turbine 13, a plurality of stationary blades 21 and moving blades 22 are alternately arranged in a turbine casing 20. The exhaust chamber 14 has an exhaust diffuser 23 that is continuous with the turbine 13. A rotor (turbine shaft) 24 is positioned so as to pass through the center of the compressor 11, the combustor 12, the turbine 13, and the exhaust chamber 14, and an end portion on the compressor 11 side is freely rotatable by a bearing portion 25. On the other hand, the end portion on the exhaust chamber 14 side is rotatably supported by the bearing portion 26. A plurality of disk plates are fixed to the rotor 24, the rotor blades 18 and 22 are connected, and a drive shaft of a generator (not shown) is connected to the end on the exhaust chamber 14 side.

  Therefore, the air taken in from the air intake port 15 of the compressor 11 passes through the plurality of stationary blades 21 and the moving blades 22 and is compressed to become high-temperature and high-pressure compressed air. Combustion occurs when a predetermined fuel is supplied to the compressed air. The high-temperature and high-pressure combustion gas that is the working fluid generated in the combustor 12 passes through the plurality of stationary blades 21 and the moving blades 22 constituting the turbine 13 to drive and rotate the rotor 24. While the generator connected to 24 is driven, the exhaust gas is converted into static pressure by the exhaust diffuser 23 in the exhaust chamber 14 and then released to the atmosphere.

  In the compressor 11 described above, as shown in FIG. 4, the compressor rotor 31 as a gas turbine rotor is configured by fastening a plurality of rotor disks 32 with spindle bolts (fastening bolts) 33 and nuts 34. . That is, the rotor disk 32 is provided with the above-described moving blade 18 on the outer peripheral portion, and is arranged in a state in which a plurality of the rotor disks 32 are in contact along the axial direction of the rotor rotation shaft. The spindle bolt 33 extends along the axial direction of the rotor rotation shaft, passes through the plurality of rotor disks 32, and a nut 34 is screwed to each end. A plurality of spindle bolts 33 are arranged at equal intervals along the circumferential direction of the rotor rotation shaft.

  Thus, the compressor rotor 31 can be rotated integrally by the spindle bolt 33 passing through the plurality of rotor disks 32 and the nuts 34 being screwed into the respective end portions.

  By the way, the spindle bolt 33 for fastening a plurality of rotor disks 32 in a stacked manner is deformed so that the intermediate portion is bent downward by the load of the rotor disk 32 and the spindle bolt 33 when the compressor rotor 31 rotates. Then, since the threaded portion of the spindle bolt 33 is supported on the end face of the rotor disk 32 by the nut 34, the compressive stress and the tensile stress act repeatedly here, and fretting fatigue is likely to occur.

  Therefore, in this embodiment, as shown in FIGS. 1 and 2, the spindle bolt 33 has a screw portion 41 in which the nut 34 is screwed to the end portion, and a diameter smaller than the screw portion 41 adjacent to the screw portion 41. A neck portion 42 for threading, a stress concentration reducing portion 43 having a smaller diameter than the through hole 32a of the rotor disk 32 adjacent to the neck portion 42, and a stress receiving portion 44 fitted into the through hole 32a of the rotor disk 32. And are provided.

  In this case, in the through hole 32a of the rotor disk 32, the screw portion 41 and the neck portion 42 are located on one side in the axial direction, the stress receiving portion 44 is located on the other side in the axial direction, and stress is applied to the intermediate portion in the axial direction. A concentration reduction unit 43 is located.

  Further, the neck portion 42 and the stress concentration reducing portion 43 have the same diameter, and are smaller than the through hole 32 a of the rotor disk 32. Further, the stress concentration reduction portion 43 extends from the neck portion 42 beyond the intermediate position in the axial direction of the through hole 32 a of the rotor disk 32.

  That is, as described above, the spindle bolt 33 has an end portion in the axial direction passing through the through holes 32a of the plurality of rotor disks 32, an end portion projects from the through hole 32a, and the nut 34 is screwed into the screw portion 41. The nut 34 is brought into close contact with the end face (seat surface) of the rotor disk 32 to fasten the plurality of rotor disks 32.

  In general, when the spindle bolt 33 is manufactured, the threaded portion is machined after the neck portion 42 having a small outer diameter is machined, so that the cutting edge of the tool can be easily removed when the threaded portion is machined. Can be formed. In this embodiment, a stress concentration reducing portion 43 having a smaller diameter than the through hole 32a of the rotor disk 32 is provided adjacent to the neck portion. In this case, considering the workability, the outer diameter of the neck portion 42 and the outer diameter of the stress concentration reducing portion 43 are the same. A stress receiving portion 44 is provided adjacent to the stress concentration reducing portion 43 and fitted into the through hole 32 a of the rotor disk 32. In this case, the stress receiving portion 44 has an outer diameter slightly smaller than that of the through hole 32 a of the rotor disk 32 so that the stress receiving part 44 can be fitted into the through hole 32 a of the rotor disk 32.

Therefore, as shown in detail in FIG. 2, with respect to the length A of the through hole 32a of the rotor disk 32, and sets the length B ₁ of the neck portion 42, the stress concentration reduction unit 43 the length B ₂ set, and sets the length B ₃ of stress receiving portion 44. Therefore, in the through hole 32a of the rotor disk 32, the screw portion 41 and the neck portion 42 are located on one side in the axial direction, that is, the nut 34 side, and the stress receiving portion 44 is located on the other side in the axial direction. The stress concentration reduction part 43 will be located in the intermediate part. In this case, the stress concentration reducing portion 43 is preferably provided so as to extend from the neck portion 42 to the stress receiving portion 44 side beyond the intermediate position C in the axial direction in the through hole 32a of the rotor disk 32.

  As described above, in the compressor rotor 31 of the first embodiment, the plurality of rotor disks 32 are arranged in the axial direction, the spindle bolt 33 penetrates the plurality of rotor disks 32, and the nut 34 is attached to the screw portion 41. The spindle bolt 33 is configured to be fastened by screwing, the spindle portion 33 is adjacent to the screw portion 41 and has a neck portion 42 for screw machining having a smaller diameter than the screw portion 41, and the rotor disc 32 is adjacent to the neck portion 42. A stress concentration reducing portion 43 having a diameter smaller than that of the through hole 32 a and a stress receiving portion 44 that fits into the through hole 32 a of the rotor disk 32 are provided.

  Therefore, when the gas turbine is operated and the compressor rotor 31 is rotated, the central portion of the spindle bolt 33 is curved and deformed due to the weight of the rotor disk 32 and the spindle bolt 33, and the spindle bolt 33 and the rotor disk 32 are penetrated. Fluctuating stress acts on the contact portion with the hole 32a. However, in this embodiment, the spindle bolt 33 is provided with the neck portion 42 and the stress concentration reducing portion 43 with respect to the screw portion 41, so that the stress is received by the stress receiving portion 44 that is separated from the screw portion 41 by a predetermined distance. Receive. Therefore, the spindle bolt 33 has a slow response to the stress transmitted from the stress receiving portion 44 to the threaded portion 41, and the stress acting on the spindle bolt 33 can be reduced to improve the reliability.

  In the gas turbine rotor according to the first embodiment, the threaded portion 41 and the neck portion 42 are located on one side in the axial direction and the stress receiving portion 44 is located on the other side in the axial direction in the through hole 32a of the rotor disk 32. The stress concentration reduction part 43 is located in the middle part of the axial direction. Therefore, by providing the stress concentration reducing portion 43 at the axial intermediate portion of the through hole 32a, the stress concentration in the vicinity of the screw portion 41 of the spindle bolt 33 can be reduced.

  Further, in the gas turbine rotor according to the first embodiment, the neck portion 42 and the stress concentration reducing portion 43 have the same diameter and are smaller in diameter than the through hole 32 a of the rotor disk 32. Therefore, by making the neck portion 42 and the stress concentration reducing portion 43 have the same diameter, the machining of the spindle bolt 33 can be facilitated and the workability can be improved.

  In the gas turbine rotor according to the first embodiment, the stress concentration reducing portion 43 extends from the neck portion 42 beyond the intermediate position in the axial direction of the through hole 32a of the rotor disk 32. Therefore, the spindle bolt 33 receives stress at the stress receiving portion 44 located away from the screw portion 41 by the stress concentration reducing portion 43, and the stress concentration can be reduced.

  FIG. 5 is a cross-sectional view illustrating a main part of a compressor rotor as a gas turbine rotor according to a second embodiment of the present invention. In addition, the same code | symbol is attached | subjected to the member which has the same function as what was demonstrated in the Example mentioned above, and the overlapping description is abbreviate | omitted.

  In the present embodiment, as shown in FIG. 5, a threaded portion 51 in which a nut 34 is screwed onto an end portion by a spindle bolt 50, and a screw diameter smaller than that of the threaded portion 51 adjacent to the threaded portion 51. A neck portion 52, a stress concentration reducing portion 53 having a smaller diameter than the through hole 32 a of the rotor disk 32, and a stress receiving portion 54 that fits into the through hole 32 a of the rotor disk 32 are provided adjacent to the neck portion 52. .

  In this case, in the through hole 32a of the rotor disk 32, the screw portion 51 and the neck portion 52 are located on one side in the axial direction, the stress receiving portion 54 is located on the other side in the axial direction, and stress is applied to the intermediate portion in the axial direction. A concentration reduction unit 53 is located. Further, the neck portion 52 and the stress concentration reducing portion 53 have the same diameter, and are smaller than the through hole 32 a of the rotor disk 32. Further, the stress concentration reducing portion 53 extends from the neck portion 52 to an intermediate position in the axial direction of the through hole 32a of the rotor disk 32 to the vicinity of the intermediate position.

  As described above, in the compressor rotor 31 according to the second embodiment, the plurality of rotor disks 32 are arranged in the axial direction, and the spindle bolt 50 passes through the plurality of rotor disks 32, and the nuts 34 are attached to the screw portions 51. The spindle bolt 50 is configured to be fastened by screwing, the spindle portion 50 is adjacent to the screw portion 51 and has a neck portion 52 for screw machining having a smaller diameter than the screw portion 51, and the rotor disc 32 is adjacent to the neck portion 52. A stress concentration reducing portion 53 having a diameter smaller than that of the through hole 32a and a stress receiving portion 54 that fits into the through hole 32a of the rotor disk 32 are provided.

  Therefore, when the compressor rotor rotates, the spindle bolt 50 receives stress at the stress receiving portion 54 that is separated from the screw portion 51 by a predetermined distance via the neck portion 52 and the stress concentration reducing portion 53. Therefore, in the spindle bolt 50, the response of the stress transmitted from the stress receiving portion 54 to the threaded portion 51 becomes slow, and the stress acting on the spindle bolt 50 can be reduced to improve the reliability.

  In each of the above-described embodiments, the plurality of spindle bolts 33 pass through positions shifted from the centers of the plurality of rotor disks 32, and the nuts 34 are screwed into the end portions to be fastened. Although configured, the present invention is not limited to this configuration. In other words, the compressor rotor may be configured by a single spindle bolt passing through the center position of a plurality of rotor disks and screwing and fastening a nut to the end.

  Moreover, in each Example mentioned above, although demonstrated using the compressor rotor 31 of the compressor 11 as a rotor for gas turbines, you may apply to the turbine rotor of the turbine 13. FIG.

  The rotor for a gas turbine and the gas turbine according to the present invention are fastened by providing a stress concentration reducing portion having a smaller diameter than the through hole of the rotor disc adjacent to the neck portion for threading on the fastening bolt for fastening the rotor disc. It is intended to improve the reliability by reducing the stress acting on the bolt, and can be applied to any kind of gas turbine.

It is sectional drawing showing the principal part of the compressor rotor as a rotor for gas turbines based on Example 1 of this invention. It is an enlarged view showing the edge part of a spindle bolt. 1 is a schematic configuration diagram illustrating a gas turbine according to a first embodiment. 1 is a cross-sectional view illustrating a gas turbine rotor according to a first embodiment. It is sectional drawing showing the principal part of the compressor rotor as a rotor for gas turbines based on Example 2 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Compressor 12 Combustor 13 Turbine 31 Compressor rotor (gas turbine rotor)
32 Rotor disk 32a Through hole 33, 50 Spindle bolt (fastening bolt)
34 Nut 41, 51 Thread part 42, 52 Neck part 43, 53 Stress concentration reducing part 44, 54 Stress receiving part

Claims (5)

A plurality of rotor disks having rotor blades on the outer periphery are arranged in the axial direction of the rotor rotating shaft, and a fastening bolt penetrates the plurality of rotor disks, and a nut is attached to a screw portion formed at an end of the fastening bolt In the gas turbine rotor fastened by screwing,
The fastening bolt has a neck portion for threading smaller in diameter than the screw portion adjacent to the screw portion, a stress concentration reducing portion smaller in diameter than the through hole of the rotor disk adjacent to the neck portion, Having a stress receiving portion that fits into the through hole of the rotor disk,
The rotor for gas turbines characterized by the above-mentioned.   In the through hole of the rotor disk, the threaded portion and the neck portion are located on one side in the axial direction, the stress receiving portion is located on the other side in the axial direction, and the stress concentration reducing portion is located in the middle portion in the axial direction. The rotor for a gas turbine according to claim 1, wherein   3. The gas turbine rotor according to claim 1, wherein the neck portion and the stress concentration reducing portion have the same diameter and a smaller diameter than the through hole of the rotor disk.   4. The gas turbine according to claim 1, wherein the stress concentration reduction portion extends from the neck portion beyond an intermediate position in an axial direction in a through hole of the rotor disk. 5. Rotor. In a gas turbine that obtains rotational power by supplying fuel to a compressed air compressed by a compressor and burning it by a combustor and supplying the generated combustion gas to the turbine.
In the rotor of the compressor, a plurality of rotor disks having moving blades on the outer peripheral portion are arranged in the axial direction of the rotor rotating shaft, and fastening bolts pass through the plurality of rotor disks, and are connected to end portions of the fastening bolts. The nut is screwed together with the formed screw part,
The fastening bolt has a neck portion for threading smaller in diameter than the screw portion adjacent to the screw portion, a stress concentration reducing portion smaller in diameter than the through hole of the rotor disk adjacent to the neck portion, Having a stress receiving portion that fits into the through hole of the rotor disk,
A gas turbine characterized by that.

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