Rotor and compressor

Abstract

To improve the strength of an impeller against a load due to centrifugal force while actualizing stable high-speed rotation.SOLUTION: A rotor includes a plurality of impellers each having a disc with a middle shaft structure and adjacent to each other in the axial direction, and a bolt fixing part having a plurality of bolts for fixing the plurality of impellers in a lump, the disc having a first fitting part having a plurality of first protruded portions and first recessed portions, a second fitting part having a plurality of second protruded portions and second recessed portions, and a plurality of bolt holes which are formed penetrating through the first fitting part and the second fitting part in the axial direction and through which the bolts are inserted, the first protruded portions being fitted to the second recessed portions of the other adjacent impeller in the state of mutually restricting the peripheral movement, the first recessed portions being fitted to the second protruded portions of the other adjacent impeller in the state of mutually restricting the peripheral movement.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a rotor and a compressor.

Background Art

[0002] Generally, a centrifugal compressor includes a rotor having a plurality of impellers, and a casing that covers the impellers from the outside to form a flow path between the casing and the impellers. In the centrifugal compressor, a fluid supplied from the outside through the flow path formed in the casing is compressed by the rotation of the impellers.

[0003] For example, as described in Patent Document 1, in such a centrifugal compressor, the rotor is formed by laminating a plurality of impellers in the axial direction. In this centrifugal compressor, the plurality of laminated impellers are fixed by large bolts that are shafts arranged so as to pass through large holes formed at the centers of the impellers.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, when a large hole for inserting a shaft is opened at the center of the impeller as described above, a thin portion is formed around the hole. And the load due to the centrifugal force when the rotor is rotated acts mainly on the thin portion around the hole. Also, this load increases in proportion to the centrifugal force that increases as the rotational speed of the rotor increases. Therefore, when trying to rotate at high speed a rotor having an impeller fixed by a shaft, there is a possibility that the impeller cannot withstand the large load due to the centrifugal force and is damaged.

[0006] This disclosure was made to solve the above problems and aims to provide a rotor and compressor that can stably rotate at high speed while improving the strength of the impeller against load due to centrifugal force. [Means for solving the problem]

[0007] To solve the above problems, the rotor according to the present disclosure is a rotor that is rotatable about an axis, and has a disk having a central shaft structure formed in the shape of a disc with a center filled in, a plurality of impellers adjacent to each other in the axial direction in which the axis extends, and a bolt fixing portion having a plurality of bolts for fixing the plurality of impellers arranged in the axial direction together, the disk having a first fitting portion having a plurality of first convex portions that protrude in the axial direction and a plurality of first recesses that are recessed from a surface facing the first side in the axial direction, and a second fitting portion formed at a position that overlaps with the first fitting portion when viewed from the axial direction, and having a plurality of second convex portions that protrude in the axial direction and a plurality of second recesses that are recessed from a surface facing the second side in the axial direction The impeller has a fitting portion and a plurality of bolt holes formed so as to penetrate the first fitting portion and the second fitting portion in the axial direction, through which the bolt is inserted, wherein the first protrusion and the first recess are arranged alternately in the circumferential direction centered on the axis at a position off-axis when viewed from the axial direction, the second protrusion and the second recess are arranged alternately in the circumferential direction at a position off-axis when viewed from the axial direction, the first protrusion fits into the second recess of an adjacent impeller in a manner that restricts each other's movement in the circumferential direction, and the first recess fits into the second protrusion of an adjacent impeller in a manner that restricts each other's movement in the circumferential direction. The first fitting portion has a plurality of first hole-forming surfaces on which the bolt holes are formed, a plurality of first separation surfaces that are arranged separately in the circumferential direction so as to be staggered with respect to the first hole-forming surfaces when viewed from the axial direction and are formed at positions offset in the axial direction with respect to the first hole-forming surfaces, and a plurality of first connecting surfaces that are arranged between the first hole-forming surfaces and the first separation surfaces in the circumferential direction and connect the first hole-forming surfaces and the first separation surfaces; the second fitting portion has a plurality of second hole-forming surfaces that are arranged in a position overlapping with the first hole-forming surfaces when viewed from the axial direction and on which the bolt holes are formed, a plurality of second separation surfaces that are arranged in a position overlapping with the first separation surfaces when viewed from the axial direction and are formed at positions offset in the axial direction with respect to the second hole-forming surfaces, and a plurality of second connecting surfaces that are arranged in a position overlapping with the first connecting surface when viewed from the axial direction and connect the second hole-forming surfaces and the second separation surfaces; and the plurality of first hole-forming surfaces and the plurality of second hole-forming surfaces of adjacent impellers face each other. .

[0008] Furthermore, the compressor according to this disclosure comprises the rotor and a casing that covers the rotor from the radially outer side with respect to the axis. [Effects of the Invention]

[0009] The rotor and compressor of this disclosure make it possible to improve the strength of the impeller against centrifugal force loads while maintaining stable high-speed rotation. [Brief explanation of the drawing]

[0010] [Figure 1] This is a cross-sectional view showing the schematic configuration of a compressor according to the present disclosure. [Figure 2] This is a cross-sectional view showing the rotor of this embodiment. [Figure 3] This is a cross-sectional view showing the first impeller of the first embodiment. [Figure 4] This figure shows the disk portion of the first impeller in Figure 3 as viewed from the first side in the axial direction. [Figure 5] This is a perspective view showing the first mating portion of the first impeller. [Figure 6] This figure shows the disk portion of the first impeller in Figure 3 as viewed from the second side in the axial direction. [Figure 7] This is a close-up view of the main part showing how the first and second fitting parts of adjacent first impellers fit together. [Figure 8] This figure shows the disk portion of the first impeller of the second embodiment as viewed from the first side in the axial direction. [Figure 9] This figure shows the disk portion of the first impeller of the second embodiment as viewed from the second side in the axial direction. [Modes for carrying out the invention]

[0011] The following describes embodiments for implementing the compressor according to this disclosure with reference to the attached drawings. However, this disclosure is not limited to these embodiments.

[0012] <First Embodiment> (Compressor configuration) The compressor 1 compresses gas as the working fluid. The compressor 1 of the present embodiment is a single-shaft multi-stage centrifugal compressor (multi-stage centrifugal compressor) that compresses hydrogen gas. As shown in FIG. 1, the compressor 1 includes a casing 2, a rotor 3, a seal portion 8, and a bearing portion 9.

[0013] Hereinafter, the direction in which the axis O of the rotor 3 described later extends is defined as the axial direction Da. The radial direction of the compressor 1 with respect to the axis O is simply referred to as the radial direction Dr. Further, the direction around the rotor 3 centered on the axis O is defined as the circumferential direction Dc.

[0014] (Configuration of the casing) The casing 2 covers the rotor 3 from the outside in the radial direction Dr. The casing 2 of the present embodiment has an outer casing 21, a plurality of diaphragms 22, and a plurality of heads 23.

[0015] The outer casing 21 has a cylindrical shape centered on a central axis arranged in the same manner as the axis O of the rotor 3. The first side Da1 (one side) in the axial direction Da of the outer casing 21 is opened to a size through which the bundle 100 described later can be inserted. An end plate 211 is formed on the second side Da2 (the other side) in the axial direction Da of the outer casing 21. The end plate 211 has a plate shape that extends perpendicular to the axial direction Da. An insertion hole 212 having a size through which the rotor 3 can be inserted and the bundle 100 cannot be inserted is formed in the central portion of the end plate 211. Thus, the bundle 100 can be inserted and removed with respect to the casing 2 by being moved in the axial direction Da with respect to the outer casing 21.

[0016] A plurality of diaphragms 22 are arranged to cover the rotor 3 from the outside in the radial direction Dr. The plurality of diaphragms 22 are arranged inside the outer casing 21. The diaphragm 22 forms an annular shape centered on the axis O. The plurality of diaphragms 22 are laminated so as to form a cylindrical body extending in the axial direction Da. Between adjacent diaphragms 22, the outer peripheral surfaces are fixed to each other by welding or bolts 71. By fixing the plurality of diaphragms 22 to each other, a flow path for introducing into the impeller 30 is formed inside. Further, the plurality of diaphragms 22 together with the head 23, the rotor 3, the seal portion 8, and the bearing portion 9 constitute a bundle 100. The bundle 100 is housed inside the outer casing 21. In the bundle 100, the rotor 3, the plurality of diaphragms 22, the plurality of heads 23, the seal portion 8, and the bearing portion 9 are in a state where they can move together so as to be integrated.

[0017] (Configuration of the flow path) Here, specifically, the flow path formed in the casing 2 by the diaphragm 22 will be described in order from the upstream side, which is the first side Da1 in the axial direction Da, to the downstream side, which is the second side Da2 in the axial direction Da. In the present embodiment, the diaphragm 22 forms, together with the outer casing 21, a suction port 221, a plurality of casing flow paths 222, and a discharge port 223 in order from the upstream side through which the gas flows.

[0018] The suction port 221 allows the gas before compression flowing in from the outside of the casing 2 to flow into the inside of the diaphragm 22. The suction port 221 is where the gas before flowing into the most upstream impeller 30 flows. An inlet guide vane is arranged at the suction port 221.

[0019] The casing flow path 222 is formed inside the diaphragm 22. The casing flow path 222 supplies the gas from the suction port 221 to the most upstream impeller 30, supplies the gas discharged from the upstream impeller 30 to the impeller 30 arranged downstream, or sends the gas discharged from the most downstream impeller 30 to the discharge port 223.

[0020] The discharge port 223 discharges the gas that has flowed through the inside of the diaphragm 22 and been compressed to the outside of the casing 2. The discharge port 223 also discharges the gas that has been discharged from the downstream impeller 30 to the outside.

[0021] The pair of heads 23 are annular members and are arranged inside the outer casing 21. The heads 23 are formed to a size that can close the openings at both ends of the outer casing 21. The heads 23 of this embodiment include a suction-side head 231 arranged on the first side Da1 in the axial direction Da with respect to the plurality of diaphragms 22, and a discharge-side head 232 arranged on the second side Da2 in the axial direction Da with respect to the plurality of diaphragms 22.

[0022] The suction head 231 is positioned closer to the suction port 221 than the discharge head 232. The suction head 231, together with the diaphragm 22 located at the first side Da1 in the axial direction Da, forms the suction port 221. The suction head 231 is fixed to the multiple integrated diaphragms 22 by bolts 71, etc. In this way, the suction head 231 is integrated with the diaphragms 22.

[0023] The discharge head 232 is positioned closer to the discharge port 223 than the suction head 231. The discharge head 232, together with the diaphragm 22 located at the second-to-last axial Da Da2, forms the discharge port 223. The discharge head 232 is fixed to the multiple integrated diaphragms 22 by bolts 71 or the like. As a result, the discharge head 232 is integrated with the diaphragms 22.

[0024] (Rotor configuration) The rotor 3 is housed inside the casing 2. The rotor 3 is rotatable about axis O. As shown in Figure 2, the rotor 3 of this embodiment has a plurality of impellers 30, a balance piston 50, a coupling hub 60, and a bolt fixing portion 70.

[0025] The impeller 30 compresses the gas by utilizing centrifugal force through rotation. Multiple impellers 30 are adjacent to each other in the axial direction Da. The impeller 30 is a so-called closed impeller, comprising a disk 4, blades 34, and a cover 35. The basic configuration of the impeller 30 will be explained below based on Figures 3 to 7, which show the first impeller 31 described later.

[0026] As shown in Figure 3, the disk 4 has a central shaft structure formed in a disc shape with axis O as the center and the center filled. The disk 4 in this embodiment has a disk shaft portion 41 and a disk outer circumference portion 42.

[0027] The disk shaft portion 41 is the solid portion of the disk 4, including the central part. The disk shaft portion 41 is formed in a circular cross-section centered on the axis O. The disk shaft portion 41 of this embodiment has a disk surface 43, a first fitting portion 45, a second fitting portion 46, a first central recess 471, a second central recess 472, and bolt holes 44.

[0028] At least one disk surface 43 is formed on the disk shaft portion 41. When viewed from the axial direction Da, the disk surface 43 is a plane centered on the axis O. The disk surface 43 is oriented in the axial direction Da. The disk surfaces 43 of adjacent impellers 30 face each other in the axial direction Da. In other words, when multiple impellers 30 are adjacent in the axial direction Da, the disk surface 43 of one impeller 30 and the disk surface 43 of another impeller 30 adjacent to that one impeller 30 face each other in the axial direction Da.

[0029] The first fitting portion 45 protrudes or recesses in the axial direction Da, thereby engaging with the second fitting portion 46 of adjacent impellers 30 and mutually restricting movement in the circumferential direction Dc. As shown in Figures 4 and 5, the first fitting portion 45 has a plurality of first convex portions 451 that protrude in the axial direction Da from the surface facing the first side Da1 in the axial direction Da, and a plurality of first concave portions 452 that are recessed in the axial direction Da (eight of each in this embodiment). The first fitting portion 45 is formed on the disk surface 43 (first disk surface 431, described later) facing the first side Da1 in the axial direction Da. When viewed from the axial direction Da, the first fitting portion 45 is located outside the radial direction Dr relative to the axis O, forming an annular region centered on the axis O.

[0030] The first protrusions 451 and first recesses 452 are positioned off-axis from the axis O when viewed from the axial direction Da, and are arranged alternately in the circumferential direction Dc centered on the axis O. As shown in Figure 7, the first protrusions 451 project from the disk surface 43 toward the first side Da1 in the axial direction Da. Multiple first protrusions 451 are arranged at equal distances in the circumferential direction Dc. The first protrusions 451 of one impeller 30 are fitted into the second recesses 462 of another impeller 30 adjacent to that impeller 30, which will be described later, in a manner that mutually restricts their movement in the circumferential direction Dc. The first recesses 452 are recessed toward the second side Da2 in the axial direction Da relative to the first protrusions 451. Multiple first recesses 452 are arranged at equal distances in the circumferential direction Dc. The first recess 452 of one impeller 30 is fitted with the second protrusion 461 of another impeller 30 adjacent to that impeller 30, which will be described later, in such a way that their movement in the circumferential direction Dc is mutually restricted.

[0031] Furthermore, as shown in Figures 4, 5, and 7, the first fitting portion 45 has a plurality of first hole-forming surfaces 453, a plurality of first separation surfaces 454, a plurality of first connecting surfaces 455, and a first central recess 471. The plurality of first hole-forming surfaces 453, the plurality of first separation surfaces 454, and the plurality of first connecting surfaces 455 form a plurality of first protrusions 451 and first recesses 452.

[0032] The first hole-forming surface 453 has a bolt hole 44 formed on it. In this embodiment, the first hole-forming surface 453 is a plane facing the first side Da1 in the axial direction Da. The first hole-forming surface 453 is formed to a size such that the bolt hole 44 is housed inside when viewed from the axial direction Da. The first hole-forming surface 453 is the top surface of the first protrusion 451, located at the first side Da1 in the axial direction Da.

[0033] The first separation surface 454 is positioned away from the first hole-forming surface 453 in the circumferential direction Dc, so as to be staggered relative to the first hole-forming surface 453 when viewed from the axial direction Da. The first separation surface 454 is formed at a position offset from the first hole-forming surface 453 in the axial direction Da. In this embodiment, the first separation surface 454 is formed at a position offset from the first hole-forming surface 453 to the second side Da2 in the axial direction Da. The first separation surface 454 is a plane facing the first side Da1 in the axial direction Da. When viewed from the axial direction Da, the first separation surface 454 is formed to be smaller than the first hole-forming surface 453. The first separation surface 454 is the bottom surface located at the second side Da2 in the axial direction Da of the first recess 452.

[0034] The first connecting surface 455 is positioned between the first hole-forming surface 453 and the first separation surface 454 in the circumferential direction Dc. The first connecting surface 455 connects the first hole-forming surface 453 and the first separation surface 454. In this embodiment, the first connecting surface 455 is formed as a plane such that, when viewed from the axial direction Da, the connection line with the first hole-forming surface 453 and the connection line with the first separation surface 454 are straight lines. In other words, the first connecting surface 455 is an inclined surface that extends straight in the radial direction Dr, facing the axial direction Da and the circumferential direction Dc.

[0035] The first protrusion 451 is formed by the first hole-forming surface 453 and two first connecting surfaces 455. The first recess 452 is formed by the first separation surface 454 and two first connecting surfaces 455. In the first fitting portion 45, the first hole-forming surface 453, the first connecting surface 455, the first separation surface 454, the first connecting surface 455, and the first hole-forming surface 453 are repeatedly arranged in the circumferential direction Dc in that order, forming multiple first protrusions 451 and first recesses 452 in a shape similar to a hearth coupling.

[0036] The first central recess 471 is located in the radial direction Dr relative to the first convex portion 451 and the first recess 452 when viewed from the axial direction Da. In other words, the first central recess 471 is the region surrounded by the first fitting portion 45 in the radial direction Dr. The first central recess 471 is recessed to the second side Da2 of the axial direction Da relative to the first recess 452. The bottom surface of the first central recess 471 in the axial direction Da is a part of the disk surface 43. Therefore, the disk surface 43, which is the bottom surface of the first central recess 471, is located to the second side Da2 of the axial direction Da relative to the first separation surface 454. The first central recess 471 is formed to be spaced apart in the axial direction Da relative to other adjacent disks 4.

[0037] As shown in Figures 6 and 7, the second fitting portion 46 has a plurality of second protrusions 461 projecting in the axial direction Da from the surface facing the second side Da2 in the axial direction Da, and a plurality of second recesses 462 recessed in the axial direction Da (eight of each in this embodiment). The second fitting portion 46 is formed on the disk surface 43 (second disk surface 432, described later) facing the second side Da2 in the axial direction Da. When viewed from the axial direction Da, the second fitting portion 46 is located outside the radial direction Dr relative to the axis O, forming an annular region centered on the axis O. When viewed from the axial direction Da, the second fitting portion 46 is formed in a position that overlaps with the first fitting portion 45.

[0038] The second protrusions 461 and second recesses 462 are positioned off-axis from the axis O when viewed from the axial direction Da, and are arranged alternately in the circumferential direction Dc centered on the axis O. The second protrusions 461 project from the disk surface 43 to the second side Da2 in the axial direction Da. Multiple second protrusions 461 are arranged at equal distances in the circumferential direction Dc. The second protrusions 461 are positioned to overlap with the first recesses 452 when viewed from the axial direction Da. The second recesses 462 are recessed to the first side Da1 in the axial direction Da relative to the second protrusions 461. Multiple second recesses 462 are arranged at equal distances in the circumferential direction Dc. The second recesses 462 are positioned to overlap with the first protrusions 451 when viewed from the axial direction Da.

[0039] Furthermore, the second fitting portion 46 has a plurality of second hole-forming surfaces 463, a plurality of second separation surfaces 464, a plurality of second connecting surfaces 465, and a second central recess 472. The plurality of second hole-forming surfaces 463, a plurality of second separation surfaces 464, and a plurality of second connecting surfaces 465 form a plurality of second protrusions 461 and second recesses 462.

[0040] The second hole-forming surface 463 has a bolt hole 44 formed on it. In this embodiment, the second hole-forming surface 463 is a plane facing the second side Da2 in the axial direction Da. The second hole-forming surface 463 is sized such that the bolt hole 44 is contained within it when viewed from the axial direction Da. The second hole-forming surface 463 is the same size as the first hole-forming surface 453 when viewed from the axial direction Da. Furthermore, the second hole-forming surface 463 is positioned to overlap with the first hole-forming surface 453 when viewed from the axial direction Da. The second hole-forming surface 463 is the bottom surface located at the first side Da1 in the axial direction Da of the second recess 462.

[0041] The second separation surface 464 is positioned away from the second hole-forming surface 463 in the circumferential direction Dc, so as to be staggered with respect to the second hole-forming surface 463 when viewed from the axial direction Da. The second separation surface 464 is formed at a position offset from the second hole-forming surface 463 in the axial direction Da. In this embodiment, the second separation surface 464 is formed at a position offset from the second side Da2 of the axial direction Da with respect to the second hole-forming surface 463. The second separation surface 464 is a plane facing the second side Da2 of the axial direction Da. When viewed from the axial direction Da, the second separation surface 464 is formed to be smaller than the second hole-forming surface 463. When viewed from the axial direction Da, the second separation surface 464 is formed to be the same size as the first separation surface 454. The second separation surface 464 is the apex surface of the second protrusion 461, located at the second side Da2 of the axial direction Da. The second separation surface 464 is positioned so as to overlap with the first separation surface 454 when viewed from the axial direction Da.

[0042] The second connecting surface 465 is positioned between the second hole-forming surface 463 and the second separation surface 464 in the circumferential direction Dc. The second connecting surface 465 connects the second hole-forming surface 463 and the second separation surface 464. In this embodiment, the second connecting surface 465 is formed as a plane such that, when viewed from the axial direction Da, the connection line with the second hole-forming surface 463 and the connection line with the second separation surface 464 are straight lines. In other words, the second connecting surface 465 is an inclined surface that extends straight in the radial direction Dr, facing the axial direction Da and the circumferential direction Dc. The second connecting surface 465 is positioned to overlap with the first connecting surface 455 when viewed from the axial direction Da. The second connecting surface 465 is formed to be the same size as the first connecting surface 455 when viewed from the axial direction Da.

[0043] The second recess 462 is formed by the second hole-forming surface 463 and the two second connecting surfaces 465. The second convex portion 461 is formed by the second separation surface 464 and the two second connecting surfaces 465. Therefore, in the second fitting portion 46, the order of the second convex portion 461 and the second recess 462 in the circumferential direction Dc is the reverse of the order of the first convex portion 451 and the first recess 452 in the circumferential direction Dc of the first fitting portion 45. In the second fitting portion 46, the second hole-forming surface 463, the second connecting surface 465, the second separation surface 464, the second connecting surface 465, and the second hole-forming surface 463 are repeatedly arranged in the circumferential direction Dc in that order, forming multiple second recesses 462 and second convex portions 461 in a shape similar to a hearth coupling. As shown in Figure 7, such second fitting portions 46 fit together with the first fitting portions 45 of adjacent impellers 30, mutually restricting their movement in the circumferential direction Dc.

[0044] When the second fitting portion 46 fits with the first fitting portion 45 of the adjacent impeller 30, the first protrusion 451 fits in such a way that its movement in the circumferential direction Dc is mutually restricted from the second recess 462 of the adjacent impeller 30. The first hole-forming surface 453 faces the second hole-forming surface 463. The first recess 452 also fits in such a way that its movement in the circumferential direction Dc is mutually restricted from the second protrusion 461 of the adjacent impeller 30. The first separation surface 454 faces the second separation surface 464. Furthermore, the first connection surface 455 and the second connection surface 465 come into contact. Note that although the first connection surface 455 and the second connection surface 465 face each other at multiple points, it is not necessary for all of the first connection surface 455 and the second connection surface 465 to be in contact. In other words, when the first fitting portion 45 and the second fitting portion 46 are fitted together, it is sufficient for at least a portion of the multiple first connecting surfaces 455 to be in contact with the multiple second connecting surfaces 465 of the adjacent impeller 30.

[0045] As shown in Figure 6, the second central recess 472 is located in the radial direction Dr relative to the second convex portion 461 and the second recess 462 when viewed from the axial direction Da. In other words, the second central recess 472 is the region surrounded by the second fitting portion 46 in the radial direction Dr. The second central recess 472 is recessed to the first side Da1 in the axial direction Da relative to the second recess 462. The bottom surface of the second central recess 472 in the axial direction Da is a part of the disk surface 43. Therefore, the disk surface 43, which is the bottom surface of the second central recess 472, is located to the first side Da1 in the axial direction Da relative to the second separating surface 464. The second central recess 472 is formed to be spaced apart in the axial direction Da relative to other adjacent disks 4. In other words, in adjacent impellers 30, there is a space between the first central recess 471 of one impeller 30 and the second central recess 472 of the other impeller 30 adjacent to that one impeller 30.

[0046] As shown in Figure 3, the bolt holes 44 are through holes through which the bolts 71, described later, are inserted. Multiple bolt holes 44 are formed so as to penetrate the first fitting portion 45 and the second fitting portion 46 in the axial direction Da, at positions offset radially Dr from the axis O. More specifically, the bolt holes 44 are formed so as to penetrate the first hole-forming surface 453 and the second hole-forming surface 463. As shown in Figures 4, 5, and 6, multiple bolt holes 44 (eight in this embodiment) are formed in the circumferential direction Dc for the first fitting portion 45 and the second fitting portion 46. In this embodiment, the bolt holes 44 are formed only on the first hole-forming surface 453 and the second hole-forming surface 463. Only one bolt hole 44 is formed for each first hole-forming surface 453 or second hole-forming surface 463. The multiple bolt holes 44 are arranged at equal distances from each other. When viewed from the axial direction Da, the bolt holes 44 are circular holes that are slightly larger than the outer shape of the bolt 71.

[0047] As shown in Figure 3, the outer circumference of the disk 42 extends from the outer edge of the disk shaft 41 and protrudes radially outward in the direction Dr. The outer circumference of the disk 42 is formed integrally with the disk shaft 41, thereby constituting the disk 4 as a single component.

[0048] The blades 34 extend from the outer circumference 42 of the disk to the cover 35. Multiple blades 34 are arranged at intervals in the circumferential direction Dc around the axis O.

[0049] The cover 35 is positioned on the first side Da1 in the axial direction Da relative to the outer circumference 42 of the disk and the multiple blades 34. The cover 35 is disc-shaped and is formed to cover the multiple blades 34. The outer circumference 42 of the disk, the blades 34, and the cover 35 form an impeller flow path 301 for circulating gas inside the impeller 30. The blades 34 and the cover 35 are formed in a position that overlaps only with the outer circumference 42 of the disk when viewed from the axial direction Da, and do not overlap with the disk shaft 41.

[0050] As shown in Figure 2, in this embodiment, the impeller 30 has a plurality of first impellers 31 and a second impeller 32. The first impellers 31 are the plurality of upstream impellers 30, including the uppermost impeller 30 (three in this embodiment). The second impellers 32 are located on the second side Da2 in the axial direction Da among the plurality of impellers 30. Therefore, the second impellers 32 consist only of the lowermost impeller 30. In other words, the second impellers 32 are located on the second side Da2 in the axial direction Da relative to the plurality of first impellers 31. The first impellers 31 and the second impellers 32 have different shapes for the disk shaft portion 41.

[0051] The disk shaft portion 41 of the first impeller 31 (hereinafter referred to as the first disk shaft portion 41A) is formed in a cylindrical shape with axis O as its center. The first disk shaft portion 41A is formed to have an axial length Da that is approximately the same as that of one diaphragm 22. In other words, when viewed from the radial direction Dr, the first disk shaft portion 41A is formed to protrude from the blade 34 on the second side Da2 in the axial direction Da. The first disk shaft portion 41A has two disk surfaces 43: a first disk surface 431 and a second disk surface 432.

[0052] The first disk surface 431 is a plane facing the first side Da1 in the axial direction Da. When viewed from the axial direction Da, the first disk surface 431 is formed in a circular shape centered on the axis O. A first fitting portion 45 is formed on the first disk surface 431.

[0053] The second disk surface 432 is a plane facing the second side Da2 in the axial direction Da. When viewed from the axial direction Da, the second disk surface 432 is formed in a circular shape centered on axis O. The second disk surface 432 is formed to be the same size as the first disk surface 431. A second fitting portion 46 is formed on the second disk surface 432.

[0054] The disk shaft portion 41 of the second impeller 32 (hereinafter referred to as the second disk shaft portion 41B) is formed in a cylindrical shape with axis O as its center. The second disk shaft portion 41B has a second disk shaft portion body 48 and a second disk extension portion 49.

[0055] The second disk shaft body 48 is formed in a cylindrical shape centered on axis O. The second disk shaft body 48 is formed to have an axial length Da approximately the same size as one diaphragm 22. The second disk shaft body 48 has the same shape as the first disk shaft 41A. The second disk shaft body 48 has only one surface as the disk surface 43, which is the first disk surface 431. The second disk shaft body 48 has a first nut receiving recess 481 formed on the surface facing the second side Da2 of the axial direction Da, which can accommodate a nut 72 described later. The first nut receiving recess 481 is recessed from the surface of the second disk shaft body 48 facing the second side Da2 of the axial direction Da toward the first side Da1 of the axial direction Da. Multiple first nut receiving recesses 481 are formed at positions that overlap with the bolt holes 44 when viewed from the axial direction Da. The first nut receiving recess 481 is formed in a circular shape that is larger than the bolt hole 44 when viewed from the axial direction Da, with the bolt hole 44 at its center.

[0056] The second disc extension 49 extends from the second disc shaft body 48 toward the second side Da2 in the axial direction Da. When viewed from the axial direction Da, the second disc extension 49 is formed in a cylindrical shape that is smaller than the second disc shaft body 48 with axis O as its center. In other words, when viewed from the axial direction Da, the second disc extension 49 is formed radially inward Dr relative to the first nut housing recess 481 so as to be surrounded by the first nut housing recess 481. The second disc extension 49 is formed integrally with the second disc shaft body 48 as a single component. On the surface of the second disc extension 49 facing the second side Da2 in the axial direction Da, a screw hole 491 for fixing the coupling hub 60 is formed.

[0057] The balance piston 50 is positioned on the first side Da1 in the axial direction Da relative to the multiple impellers 30. In this embodiment, the balance piston 50 is adjacent to the upstreammost impeller 30 (the first impeller 31 positioned on the first side Da1 among the multiple first impellers 31). As shown in Figure 1, the balance piston 50 is positioned so that its position in the axial direction Da coincides with that of the suction head 231. As shown in Figure 2, the balance piston 50 has a piston shaft portion 51, a pressure receiving portion 52, and a piston extension portion 53.

[0058] The piston shaft portion 51 is positioned to contact the first impeller 31, which is located on the first side Da1 in the axial direction Da. The piston shaft portion 51 is formed in a cylindrical shape with axis O as its center. The piston shaft portion 51 has a first piston surface 54, a second piston surface 55, and a piston bolt hole 56.

[0059] The first piston surface 54 is a plane facing the first side Da1 in the axial direction Da. When viewed from the axial direction Da, the first piston surface 54 is formed in an annular shape centered on the axis O. The first piston surface 54 has a second nut receiving recess 541 that can accommodate a nut 72, which will be described later. The second nut receiving recess 541 is recessed from the first piston surface 54 toward the second side Da2 in the axial direction Da. When viewed from the axial direction Da, multiple second nut receiving recesses 541 are formed at positions that overlap with the bolt hole 44. When viewed from the axial direction Da, the second nut receiving recesses 541 are formed in a circular shape that is larger than the bolt hole 44, with the bolt hole 44 as the center. In other words, the second nut receiving recess 541 has the same shape as the first nut receiving recess 481.

[0060] The second piston surface 55 is a plane facing the second side Da2 in the axial direction Da. The second piston surface 55 faces the first disk surface 431 of the upstream first impeller 31. In other words, when the balance piston 50 is fixed to the impeller 30, the second piston surface 55 and the first disk surface 431 of the first impeller 31 face each other in the axial direction Da. When viewed from the axial direction Da, the second piston surface 55 is formed in a circular shape centered on the axis O. A piston fitting portion 551 that fits with the first fitting portion 45 is formed on the second piston surface 55. When viewed from the axial direction Da, the piston fitting portion 551 is formed in an annular shape centered on the axis O so as to overlap with the piston fitting portion 551. The piston fitting portion 551 is formed in the same shape as the second fitting portion 46. Therefore, the first fitting portion 45 of the first impeller 31 fits into the piston fitting portion 551 by shrink fitting or the like, thereby restricting the radial position Dr between the upstream first impeller 31 and the balance piston 50.

[0061] The piston bolt hole 56 is formed to penetrate the piston shaft portion 51 in the axial direction Da at a position offset from the axis O in the radial direction Dr. The piston bolt hole 56 penetrates from the first piston surface 54 to the second piston surface 55. Multiple piston bolt holes 56 (eight in this embodiment) are formed in the circumferential direction Dc centered on the axis O with respect to the first piston surface 54 and the second piston surface 55. When viewed from the axial direction Da, the piston bolt hole 56 is a circular hole that is slightly larger than the outer shape of the bolt 71. In this embodiment, the piston bolt hole 56 is formed to be in the same position and shape as the bolt hole 44 when viewed from the axial direction Da.

[0062] The pressure-receiving portion 52 protrudes annularly outward in the radial direction Dr relative to the piston shaft portion 51. The pressure-receiving portion 52 protrudes outward in the radial direction Dr from a part of the outer edge of the piston shaft portion 51. The axial length Da of the pressure-receiving portion 52 is shorter than the axial length Da of the piston shaft portion 51. The pressure-receiving portion 52 is formed integrally with the piston shaft portion 51 as a single component. The pressure-receiving portion 52 has a first pressure-receiving surface 521 and a second pressure-receiving surface 522.

[0063] The first pressure-receiving surface 521 is a plane facing the first side Da1 in the axial direction Da. When viewed from the axial direction Da, the first pressure-receiving surface 521 is formed in an annular shape centered on the axis O.

[0064] The second pressure-receiving surface 522 is a plane facing the second side Da2 in the axial direction Da. When viewed from the axial direction Da, the second pressure-receiving surface 522 is formed in an annular shape centered on the axis O. The second pressure-receiving surface 522 is formed such that its position in the radial direction Dr coincides with that of the first pressure-receiving surface 521.

[0065] The piston extension 53 extends from the piston shaft 51 toward the first side Da1 in the axial direction Da. When viewed from the axial direction Da, the piston extension 53 is formed in a cylindrical shape that is smaller than the piston shaft 51, with the axis O as its center. In other words, when viewed from the axial direction Da, the piston extension 53 is formed radially inward Dr relative to the second nut housing recess 541, so as to be surrounded by the second nut housing recess 541. The piston extension 53 is formed integrally with the piston shaft 51 as a single component. A thrust collar 531 is formed at the tip of the first side Da1 of the piston extension 53 in the axial direction Da, projecting radially outward Dr.

[0066] The coupling hub 60 is designed to be connectable to the rotor 3 of other rotating machinery such as a steam turbine or motor. The coupling hub 60 is formed in a cylindrical shape with axis O as its center. A flange is formed at the end of the second side Da2 of the coupling hub 60 in the axial direction Da, projecting outward in the radial direction Dr. The coupling hub 60 is detachably fixed to the second impeller 32. Specifically, the coupling hub 60 has a bolt insertion hole 61 that penetrates the coupling hub 60 with axis O as its center. The coupling hub 60 is fixed to the second disc extension 49 by fixing a fixing bolt 62 inserted through the bolt insertion hole 61 to a screw hole 491 in the second disc extension 49.

[0067] The bolt fixing section 70 securely fastens multiple impellers 30 and balance pistons 50 arranged in the axial direction Da. The bolt fixing section 70 includes a bolt 71 and a pair of nuts 72. The bolt 71 is a stud bolt, consisting only of a threaded portion and without a head. The bolt 71 has an axial length Da such that when inserted through the bolt hole 44 and the piston bolt hole 56, its end reaches the first nut receiving recess 481 and the second nut receiving recess 541. The nuts 72 are sized to fit into the first nut receiving recess 481 and the second nut receiving recess 541. The pair of nuts 72 are detachably attached to both ends of the bolt 71.

[0068] As shown in Figure 1, the seal portion 8 seals the space between the rotor 3 and the casing 2. The seal portion 8 in this embodiment has a first seal portion 81, a second seal portion 82, and a third seal portion 83.

[0069] The first seal portion 81 seals the space between the inner circumferential surface of the suction head 231 and the outer circumferential surface of the piston extension portion 53. The first seal portion 81 is a dry gas seal. The first seal portion 81 is detachable from the suction head 231 and the piston extension portion 53.

[0070] The second seal portion 82 seals the space between the inner circumferential surface of the discharge head 232 and the outer circumferential surface of the second disc extension portion 49. The second seal portion 82 is a dry gas seal. The second seal portion 82 is detachable from the discharge head 232 and the piston extension portion 53.

[0071] The third seal portion 83 seals the space between the inner circumferential surface of the suction-side head 231 and the outer circumferential surface of the pressure-receiving portion 52. The third seal portion 83 is a labyrinth seal. The third seal portion 83 is positioned at a distance of Da2 on the second side in the axial direction Da from the first seal portion 81. The third seal portion 83 is fixed to the suction-side head 231.

[0072] The bearing section 9 supports the rotor 3 so that it can rotate around the axis O relative to the casing 2. In this embodiment, the bearing section 9 has a first bearing section 91, a second bearing section 92, and a third bearing section 93.

[0073] The first bearing portion 91 is a journal bearing that rotatably supports the piston extension portion 53. The first bearing portion 91 is subjected to a radial load Dr acting on the end of the rotor 3 on the first side Da1 in the axial direction Da.

[0074] The second bearing portion 92 is a journal bearing that rotatably supports the second disc extension portion 49. The second bearing portion 92 receives a radial load Dr acting on the end of the rotor 3 on the second side Da2 in the axial direction Da. The second bearing portion 92 is mounted inside a cylindrical bearing holder 95. This bearing holder 95 is fixed to the discharge head 232 using removable fixing means such as bolts 71. Furthermore, by removing the bearing holder 95 from the discharge head 232, the second seal portion 82 can move outward relative to the discharge head 232.

[0075] The third bearing section 93 is a thrust bearing that rotatably supports the thrust collar 531 of the piston extension section 53. The third bearing section 93 receives the axial load Da acting on the rotor 3. The third bearing section 93, together with the first bearing section 91, is mounted inside a box-shaped bearing cover 96. This bearing cover 96 is fixed to the suction head 231 using removable fastening means such as bolts 71.

[0076] (Effects and Benefits) In the compressor 1 equipped with the rotor 3 configured as described above, the load due to centrifugal force accompanying the rotation of the rotor 3 increases as it moves inward in the radial direction Dr, and a thrust force in the axial direction Da is also generated on the impeller 30 due to the compressed gas. In the rotor 3 of this embodiment, the first fitting portion 45 of one impeller 30 and the second fitting portion 46 of the adjacent impeller 30 are formed at overlapping positions. As a result, the first protrusion 451 of one impeller 30 fits into the second recess 462 of the adjacent impeller 30, and the first recess 452 of one impeller 30 fits into the second protrusion 461 of the adjacent impeller 30. In other words, the movement of adjacent impellers 30 in the circumferential direction Dc is mutually restricted by the first protrusion 451 and the first recess 452, and the second protrusion 461 and the second recess 462. In this state, the multiple impellers 30 are fixed together by bolts 71 inserted through bolt holes 44 that penetrate the first fitting portion 45 and the second fitting portion 46 in the axial direction Da. Therefore, the radial outward Dr and axial Da loads generated around the bolt holes 44 can be stably received by the surfaces of the first fitting portion 45 and the second fitting portion 46 around the bolt holes 44. Consequently, torque is stably transmitted between the impellers 30, and even when the rotor 3 is rotated at high speed without a shaft, the impellers 30 are prevented from shifting. As a result, the rotor 3 can be rotated stably at high speed while improving the strength of the impellers 30 against loads caused by centrifugal force.

[0077] Furthermore, the impeller 30 has a solid structure with a disc shaft portion 41. In other words, the impeller 30 is not fixed to the outer surface of the shaft by shrink fitting or the like. Therefore, there is no large hole in the center of the impeller 30 for inserting the shaft. Multiple solid impellers 30, namely first impellers 31 and second impellers 32, are stacked in the axial direction Da, and a balance piston 50 is further stacked in the axial direction Da. The rotor 3 is formed by fastening both ends of bolts 71, which are inserted through bolt holes 44 and piston bolt holes 56, with nuts 72 to fix the stacked multiple first impellers 31 and second impellers 32 and the balance piston 50. When such a rotor 3 is rotated, the strength of the impeller 30 against the load generated by centrifugal force can be greatly improved because there is no large hole in the impeller 30.

[0078] Furthermore, the circumferential position Dc of the first impellers 31 aligned in the axial direction Da is restricted by the interlocking of the first convex portion 451 and the first recess portion 452 with the second convex portion 461 and the second recess portion 462 between the first impellers 31 and the second impeller 32. Because there are multiple such first convex portions 451 and first recess portions 452, and multiple second convex portions 461 and second recess portions 462, when the first convex portions 451 and first recess portions 452 and the second convex portions 461 and second recess portions 462 interlock, the radial position Dr of the first impellers 31 aligned in the axial direction Da is also restricted. Therefore, the radial position Dr of the first impellers 31 and the radial position Dr of the second impeller 32 and the first impeller 31 can be aligned before completely fixing the position with bolts 71. As a result, centering can be easily performed when stacking multiple impellers 30 in the axial direction Da. This improves the workability when assembling rotor 3.

[0079] Furthermore, the first hole-forming surface 453 and the second hole-forming surface 463, where the bolt holes 44 are formed, face each other. Therefore, even if a large load is applied around the bolt holes 44 and the first hole-forming surface 453 and the second hole-forming surface 463 come into contact, the surface pressure around the bolt holes 44 can be maintained by the first hole-forming surface 453 and the second hole-forming surface 463. As a result, the radial outward Dr and axial Da loads generated around the bolt holes 44 can be stably received by the first hole-forming surface 453 and the second hole-forming surface 463.

[0080] Furthermore, the first connecting surface 455 is in contact with the second connecting surface 465 of the adjacent impeller 30. In other words, the first convex portion 451 and the first concave portion 452 and the second convex portion 461 and the second concave portion 462 are immobile in the circumferential direction Dc by the first connecting surface 455 and the second connecting surface 465. Therefore, the radial Dr positions of the first impellers 31 and the radial Dr positions of the second impeller 32 and the first impeller 31 can be aligned more accurately before the position is completely fixed with bolts 71. As a result, when stacking multiple impellers 30 in the axial direction Da, centering can be easily performed with high precision. This greatly improves the workability when assembling the rotor 3.

[0081] Furthermore, the multiple first connecting surfaces 455 and the multiple second connecting surfaces 465 are formed as planes such that the connection lines with other surfaces are straight. As a result, the first hole-forming surface 453 and the first separation surface 454 are connected by the plane first connecting surface 455. Similarly, the second hole-forming surface 463 and the second separation surface 464 are connected by the plane second connecting surface 465. In other words, the first convex portion 451 and the first concave portion 452, and the second convex portion 461 and the second concave portion 462 are formed in a shape similar to a hearth coupling. Therefore, the first connecting surfaces 455 and the second connecting surfaces 465 are formed as planes that are straight toward the axis O when viewed from the radial direction Dr. This makes it easier to process the first connecting surfaces 455 and the second connecting surfaces 465, improving the workability during the manufacturing of the impeller 30.

[0082] Furthermore, the disc 4 has a first central recess 471 that is recessed radially inward from the first convex portion 451 and the first recess 452, and a second central recess 472 that is recessed radially inward from the second convex portion 461 and the second recess 462. As a result, a space is formed radially inward from the first convex portion 451 and the first recess 452 and the second convex portion 461 and the second recess 462. Therefore, when machining the first convex portion 451 and the first recess 452 and the second convex portion 461 and the second recess 462 from the material, interference between the inner area of ​​the disc 4 and the tool is suppressed. This makes machining the first convex portion 451 and the first recess 452 and the second convex portion 461 and the second recess 462 easier, improving the workability during the manufacturing of the impeller 30.

[0083] <Second Embodiment> Next, a second embodiment of the compressor according to this disclosure will be described. In the second embodiment described below, components common to the first embodiment are denoted by the same reference numerals in the figures and their descriptions are omitted. In the second embodiment, the shapes of the first fitting portion and the second fitting portion differ from those of the first embodiment.

[0084] Specifically, as shown in Figures 8 and 9, the shapes of the first connecting surface 455A and the second connecting surface 465A are different in the second embodiment. As shown in Figure 8, the first connecting surface 455A in the second embodiment is formed as a curved surface such that, when viewed from the axial direction Da, the connection line with the first hole-forming surface 453 and the connection line with the first separation surface 454 are curved. In other words, the first connecting surface 455A is a curved surface that faces the axial direction Da and the circumferential direction Dc. When viewed from the axial direction Da, the first connecting surface 455A is a convex curved surface that protrudes most in the circumferential direction Dc near the center of the radial direction Dr.

[0085] Furthermore, the first fitting portion 45A is arranged in a repeating pattern in the circumferential direction Dc, consisting of a first hole-forming surface 453, a curved first connecting surface 455A, a first separation surface 454, a curved first connecting surface 455A, and a first hole-forming surface 453, thereby forming multiple first convex portions 451 and first concave portions 452 in a shape similar to a curved coupling.

[0086] Similarly, as shown in Figure 9, the second connecting surface 465A is formed as a curved surface such that, when viewed from the axial direction Da, the connection line with the second hole-forming surface 463 and the connection line with the second separation surface 464 are curved. In other words, the second connecting surface 465A is a curved surface oriented in the axial direction Da and the circumferential direction Dc. When viewed from the axial direction Da, the second connecting surface 465A is a concave curved surface that is most concave in the circumferential direction Dc near the center of the radial direction Dr.

[0087] Furthermore, the second fitting portion 46A is arranged in a repeating pattern in the circumferential direction Dc, consisting of a second hole-forming surface 463, a curved second connecting surface 465A, a second separation surface 464, a curved second connecting surface 465A, and a second hole-forming surface 463, thereby forming multiple second convex portions 461 and second concave portions 462 in a shape similar to a curved coupling.

[0088] (Effects and Benefits) With the above configuration, the multiple first connecting surfaces 455A and the multiple second connecting surfaces 465A are formed as curved surfaces such that the connection lines with other surfaces are curved. As a result, the first hole-forming surface 453 and the first separation surface 454 are connected by the curved first connecting surface 455A. Similarly, the second hole-forming surface 463 and the second separation surface 464 are connected by the curved second connecting surface 465A. In other words, the first convex portion 451 and the first concave portion 452, and the second convex portion 461 and the second concave portion 462 are formed in a shape similar to a curved coupling. Therefore, when stacking multiple impellers 30 in the axial direction Da, centering can be easily performed with high precision. This greatly improves the workability when assembling the rotor 3.

[0089] (Other embodiments) Although embodiments of this disclosure have been described in detail above with reference to the drawings, the specific configuration is not limited to these embodiments and may include design changes and the like that do not depart from the gist of this disclosure.

[0090] The rotating machine equipped with the rotor 3 is not limited to the compressor 1. The rotating machine equipped with the rotor 3 may be, for example, a steam turbine.

[0091] Furthermore, the number of impellers 30 on the rotor 3 is not limited to four, as in the embodiment, but may be two or more. Therefore, for example, the number of impellers 30 on the rotor 3 may be five or more.

[0092] Furthermore, the number of first protrusions 451 and first recesses 452 in the first fitting portion 45, and the number of second protrusions 461 and second recesses 462 in the second fitting portion 46, are not limited to eight, as in the embodiment. The number of first protrusions 451 and first recesses 452 and the number of second protrusions 461 and second recesses 462 may be seven or fewer, or nine or more, respectively. Also, the first protrusions 451 and first recesses 452 and the second protrusions 461 and second recesses 462 are not limited to being evenly distributed in the circumferential direction Dc.

[0093] Furthermore, the bolt holes 44 are not limited to being formed only on the first hole-forming surface 453 and the second hole-forming surface 463. The bolt holes 44 only need to be formed on the first fitting portion 45 and the second fitting portion 46. Therefore, bolt holes 44 may also be formed on the first separation surface 454, the first connecting surface 455, the second separation surface 464, and the second connecting surface 465. Also, it is not limited to having only one bolt hole 44 formed on one first hole-forming surface 453 or the second hole-forming surface 463. Multiple bolt holes 44 may be formed on one first hole-forming surface 453 or the second hole-forming surface 463.

[0094] <Note> The rotor 3 and compressor 1 described in the embodiment can be understood, for example, as follows.

[0095] (1) The rotor 3 according to the first embodiment is a rotor 3 that is rotatable about an axis O, and has a disk 4 that is formed in the shape of a disc with the axis O as the center and has a central shaft structure with the center filled, and comprises a plurality of impellers 30 adjacent to each other in the axial direction Da of the axis O, and a bolt fixing portion 70 having a plurality of bolts 71 that fix together the plurality of impellers 30 arranged in the axial direction Da, and the disk 4 has a first fitting portion 45, 45A having a plurality of first convex portions 451 and recessed first recesses 452 that protrude in the axial direction Da from a surface facing the first side Da1 of the axial direction Da, and a second fitting portion 46, 46A that is formed in a position that overlaps with the first fitting portion 45, 45A when viewed from the axial direction Da, and has a plurality of second convex portions 461 and recessed second recesses 462 that protrude in the axial direction Da from a surface facing the second side Da2 of the axial direction Da The first fitting portions 45, 45A and the second fitting portions 46, 46A are formed to penetrate the axial direction Da, and the impeller has a plurality of bolt holes 44 through which the bolt 71 is inserted. The first protrusion 451 and the first recess 452 are positioned off-axis from the axis O when viewed from the axial direction Da, and are arranged alternately in the circumferential direction Dc centered on the axis O. The second protrusion 461 and the second recess 462 are positioned off-axis from the axis O when viewed from the axial direction Da, and are arranged alternately in the circumferential direction Dc. The first protrusion 451 fits into the second recess 462 of an adjacent impeller 30 in a manner that restricts each other's movement in the circumferential direction Dc. The first recess 452 fits into the second protrusion 461 of an adjacent impeller 30 in a manner that restricts each other's movement in the circumferential direction Dc.

[0096] As a result, the first protrusion 451 and first recess 452, and the second protrusion 461 and second recess 462 mutually restrict the circumferential movement Dc of adjacent impellers 30. In this state, multiple impellers 30 are fixed together by bolts 71 inserted through bolt holes 44 that penetrate the first fitting parts 45, 45A and the second fitting parts 46, 46A in the axial direction Da. Therefore, the radial outward Dr and axial Da loads generated around the bolt holes 44 can be stably received by the surfaces of the first fitting parts 45, 45A and the second fitting parts 46, 46A around the bolt holes 44. Consequently, torque is stably transmitted between the impellers 30, and even when the rotor 3 is rotated at high speed without a shaft, the impellers 30 are prevented from shifting. As a result, the rotor 3 can be rotated stably at high speed while improving the strength of the impellers 30 against centrifugal force loads.

[0097] (2) The rotor 3 according to the second embodiment is the rotor 3 of (1), wherein the first fitting portions 45, 45A have a plurality of first hole-forming surfaces 453 in which the bolt holes 44 are formed, a plurality of first separation surfaces 454 that are arranged separately in the circumferential direction Dc so as to be staggered with respect to the first hole-forming surfaces 453 when viewed from the axial direction Da, and are formed at positions offset in the axial direction Da with respect to the first hole-forming surfaces 453, and a plurality of first connecting surfaces 455, 455A that are arranged between the first hole-forming surfaces 453 and the first separation surfaces 454 in the circumferential direction Dc and connect the first hole-forming surfaces 453 and the first separation surfaces 454, and the second fitting portions 46, 46A have the axial direction D When viewed from a, there are a plurality of second hole-forming surfaces 463 that are positioned to overlap with the first hole-forming surface 453 and in which the bolt holes 44 are formed; when viewed from the axial direction Da, there are a plurality of second separation surfaces 464 that are positioned to overlap with the first separation surface 454 and in which the second hole-forming surfaces 463 are offset in the axial direction Da; and when viewed from the axial direction Da, there are a plurality of second connection surfaces 465, 465A that are positioned to overlap with the first connection surface 455 and in which the second hole-forming surfaces 463 and the second separation surfaces 464 are connected; the plurality of first hole-forming surfaces 453 and the plurality of second hole-forming surfaces 463 of adjacent impellers 30 face each other.

[0098] This ensures that surface pressure around the bolt hole 44 is maintained by the first hole-forming surface 453 and the second hole-forming surface 463. As a result, the radial Dr outward and axial Da loads generated around the bolt hole 44 can be stably received by the first hole-forming surface 453 and the second hole-forming surface 463.

[0099] (3) The rotor 3 according to the third embodiment is the rotor 3 of (2), wherein the plurality of first connection surfaces 455, 455A are in contact with at least a portion of the plurality of second connection surfaces 465, 465A of an adjacent impeller 30.

[0100] As a result, the first convex portion 451 and the first concave portion 452 and the second convex portion 461 and the second concave portion 462 are immobile in the circumferential direction Dc by the first connecting surfaces 455, 455A and the second connecting surfaces 465, 465A. Therefore, the radial Dr positions of the first impellers 31 and the radial Dr positions of the second impeller 32 and the first impeller 31 can be aligned more accurately before the position is completely fixed with the bolts 71. As a result, when stacking multiple impellers 30 in the axial direction Da, centering can be easily performed with high precision. This greatly improves the workability when assembling the rotor 3.

[0101] (4) The rotor 3 according to the fourth embodiment is the rotor 3 of (2) or (3), wherein the plurality of first connecting surfaces 455 are formed as planes such that, when viewed from the axial direction Da, the connection lines with the first hole forming surface 453 and the connection lines with the first separation surface 454 are straight lines, and the plurality of second connecting surfaces 465 are formed as planes such that, when viewed from the axial direction Da, the connection lines with the second hole forming surface 463 and the connection lines with the second separation surface 464 are straight lines.

[0102] As a result, the first convex portion 451 and the first concave portion 452, and the second convex portion 461 and the second concave portion 462 are formed in a shape similar to a hearth coupling. Therefore, the first connecting surface 455 and the second connecting surface 465 are formed as planes that are straight toward the axis O when viewed from the radial direction Dr. This makes it easier to process the first connecting surface 455 and the second connecting surface 465, improving the workability during the manufacture of the impeller 30.

[0103] (5) The rotor 3 according to the fifth embodiment is the rotor 3 of (2) or (3), wherein the plurality of first connecting surfaces 455A are formed as curved surfaces such that, when viewed from the axial direction Da, the connection lines with the first hole forming surface 453 and the connection lines with the first separation surface 454 are curved, and the plurality of second connecting surfaces 465A are formed as curved surfaces such that, when viewed from the axial direction Da, the connection lines with the second hole forming surface 463 and the connection lines with the second separation surface 464 are curved.

[0104] As a result, the first convex portion 451 and the first concave portion 452, and the second convex portion 461 and the second concave portion 462 are formed in a shape similar to a Curvic coupling. Therefore, when stacking multiple impellers 30 in the axial direction Da, centering can be easily performed with high precision. This greatly improves the workability when assembling the rotor 3.

[0105] (6) The rotor 3 according to the sixth embodiment is any one of the rotors 3 of (1) to (5), wherein the disk 4, when viewed from the axial direction Da, has a first central recess 471 in which the region inside the radial direction Dr with respect to the axis O relative to the first convex portion 451 and the first recess 452 is recessed in the axial direction Da relative to the first recess 452, and a second central recess 472 in which the region inside the radial direction Dr relative to the second convex portion 461 and the second recess 462 is recessed in the axial direction Da relative to the second recess 462.

[0106] As a result, a space is formed inward in the radial direction Dr relative to the first protrusion 451 and first recess 452, and the second protrusion 461 and second recess 462. Therefore, when machining the first protrusion 451 and first recess 452, and the second protrusion 461 and second recess 462 from the material, interference between the inner area of ​​the disc 4 and the tool is suppressed. This makes machining the first protrusion 451 and first recess 452, and the second protrusion 461 and second recess 462 easier, improving the workability during the manufacturing of the impeller 30.

[0107] (7) The compressor 1 according to the seventh embodiment comprises one rotor 3 of any one of (1) to (6), and a casing 2 that covers the rotor 3 from the outside in the radial direction Dr with respect to the axis O. [Explanation of Symbols]

[0108] 1… Compressor 2…Casing 21…External casing 211...End plate 212... Through hole 22... Diaphragm 221... Inlet 222... Casing flow path 223…Discharge port 23... Head 231... Suction head 232... Discharge head 3…Rotor 30... Impeller 31…First impeller 32... Second impeller 4…Disk 41…Disk shaft 42…Disk outer edge 43…Disk surface 45, 45A...first mating part 451...First protrusion 452...First recess 453...First pore forming surface 454...First separation surface 455, 455A...First connection surface 471...First central recess 46, 46A…Second fitting part 461... Second protrusion 462...Second recess 463…Second hole forming surface 464…Second separation surface 465, 465A... Second connection side 472...Second central recess 44… Bolt holes 34… Blade 35...cover 301... Impeller flow path 41A...First disk shaft 41B...Second disk shaft 431...First disk surface 432...Second disk side 48... Second disc shaft body 481...First nut receiving recess 49...Second disk extension 491... Screw hole 50... Balance piston 51... Piston shaft 54…First piston surface 541...Second nut receiving recess 55...Second piston surface 551... Piston fitting section 56…Piston bolt hole 52...Pressure receiving section 521...First pressure receiving surface 522...Second pressure receiving surface 53... Piston extension 531...Thrust Color 60... Coupling Hub 61…Bolt insertion hole 62… Fixing bolts 70... Bolt fixing part 71... Volts 72... Nut 8...Seal part 81...First seal section 82...Second seal section 83...Third seal section 9...Bearing part 91...First bearing part 92...Second bearing part 95...Bearing holder 93…Third bearing part 96...Bearing cover 100... Bundle O…Axis line Da... Axis Da1…first side Da2…Second side Dr…Radial direction Dc…Circumferential direction

Claims

1. A rotor that is capable of rotating around its axis, It has a disk having a central shaft structure formed in the shape of a disc with the aforementioned axis as the center and the center filled, and a plurality of impellers adjacent to each other in the axial direction in which the aforementioned axis extends, The system includes a bolt fixing section having multiple bolts that fix together multiple impellers arranged in the axial direction, The aforementioned disk is A first fitting portion having a plurality of first protrusions projecting in the axial direction and first recesses that are recessed from the surface facing the first side in the axial direction, A second fitting portion is formed in a position that overlaps with the first fitting portion when viewed from the axial direction, and has a plurality of second protrusions and second recesses that protrude in the axial direction from a surface facing the second side in the axial direction, The first fitting portion and the second fitting portion are formed to penetrate the axial direction, and have a plurality of bolt holes through which the bolt is inserted, The first protrusion and the first recess are arranged alternately in the circumferential direction centered on the axis, at positions offset from the axis when viewed from the axial direction. The second protrusion and the second recess are arranged alternately in the circumferential direction at positions that are offset from the axis when viewed from the axial direction. The first protrusion fits into the second recess of an adjacent impeller, restricting each other's movement in the circumferential direction. The first recess fits with the second protrusion of an adjacent impeller, restricting each other's movement in the circumferential direction. The first fitting portion is, The plurality of first hole-forming surfaces on which the bolt holes are formed, When viewed from the axial direction, a plurality of first spaced surfaces are arranged alternately with respect to the first hole-forming surface and are spaced apart in the circumferential direction, and are formed at positions offset in the axial direction with respect to the first hole-forming surface, The first hole-forming surface and the first separation surface are arranged in the circumferential direction and have a plurality of first connecting surfaces that connect the first hole-forming surface and the first separation surface, The second fitting portion is, When viewed from the axial direction, a plurality of second hole-forming surfaces are arranged in a position that overlaps with the first hole-forming surface, and the bolt holes are formed therein. When viewed from the axial direction, a plurality of second separating surfaces are arranged in a position that overlaps with the first separating surface and are formed at a position offset in the axial direction with respect to the second hole-forming surface, When viewed from the axial direction, it has a plurality of second connecting surfaces that are positioned to overlap with the first connecting surface and connect the second hole-forming surface and the second separation surface, A rotor in which a plurality of the first hole-forming surfaces and a plurality of the second hole-forming surfaces of other adjacent impellers face each other.

2. The rotor according to claim 1, wherein the plurality of first connecting surfaces are in contact with at least a portion of the plurality of second connecting surfaces of other adjacent impellers.

3. The multiple first connecting surfaces are formed as planes such that, when viewed from the axial direction, the connection lines with the first hole-forming surface and the connection lines with the first separation surfaces are straight lines. The rotor according to claim 1 or 2, wherein the plurality of second connecting surfaces are formed as planes such that, when viewed from the axial direction, the connection lines with the second hole-forming surface and the connection lines with the second separation surfaces are straight lines.

4. The multiple first connecting surfaces are formed as curved surfaces such that, when viewed from the axial direction, the connection lines with the first hole-forming surface and the connection lines with the first separation surfaces are curved. The rotor according to claim 1 or 2, wherein the plurality of second connecting surfaces are formed as curved surfaces such that, when viewed from the axial direction, the connection lines with the second hole-forming surface and the connection lines with the second separation surfaces are curved.

5. The rotor according to claim 1 or 2, wherein the disk, when viewed from the axial direction, has a first central recess in which a region radially inward relative to the first convex portion and the first recess with respect to the axis is recessed in the axial direction relative to the first recess, and a second central recess in which, when viewed from the axial direction, a region radially inward relative to the second convex portion and the second recess is recessed in the axial direction relative to the second recess.

6. A rotor according to claim 1 or 2, A compressor comprising a casing that covers the rotor from the radially outer side with respect to the aforementioned axis.

Images