Rotor, rotating machine, and method for assembling a rotor

Abstract

To improve assemblability while biding an impeller and a shaft firmly in the radial direction and the circumferential direction.SOLUTION: A rotor includes a shaft, a coupling shaft coupled to an end portion of the first side of the shaft in the axial direction with a screw portion formed on the tip end portion, an impeller having an impeller body and an insertion hole formed through the center portion of the impeller body in the axial direction such that the coupling shaft is inserted therein, a sleeve having a tubular shape disposed at the second side of the impeller in the axial direction and fixed to the shaft so as to cover the shaft at the outer side in the radial direction of the shaft with reference to the axis, and a nut disposed at the first side of the impeller in the axial direction and fastened to the screw portion so as to nip and fix the impeller with the sleeve in the axial direction. The positions of a sleeve end surface of the sleeve facing the first side in the axial direction and an impeller end surface of the impeller facing the second side in the axial direction are restricted with regard to one another in the circumferential direction and the radial direction in a state of contact.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present disclosure relates to a rotor, a rotating machine, and a method for assembling a rotor.

Background Art

[0002] In a rotating machine such as a centrifugal compressor, there is a device provided with an impeller for compressing a working fluid. For example, Patent Document 1 discloses a configuration of an impeller fastening structure including an impeller, a rotating shaft whose tip is inserted into the back side of the impeller, and bolts for fastening the impeller and the rotating shaft. In this configuration, the hollow cylindrical portion of the impeller is inserted inside the hollow cylindrical portion of the rotating shaft in the radial direction. The outer peripheral surface of the hollow cylindrical portion of the impeller and the inner peripheral surface of the hollow cylindrical portion of the rotating shaft are fitted by an interference fit. Thereby, the impeller and the rotating shaft are constrained in the radial direction and the circumferential direction centered on the axis of the rotating shaft.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the configuration described in Patent Document 1, the impeller and the shaft (rotating shaft) are fitted by an interference fit in order to constrain the impeller and the shaft in the radial direction and the circumferential direction. However, with such a structure, it takes time and effort to assemble the impeller to the shaft.

[0005] The present disclosure has been made to solve the above problems, and an object thereof is to provide a rotor, a rotating machine, and a method for assembling a rotor that can firmly constrain an impeller and a shaft in the radial direction and the circumferential direction while improving the assemblability.

Means for Solving the Problems

[0006] To solve the above problems, the present disclosure includes a shaft extending in the axial direction in which the axis extends, with the axis as the center; a connecting shaft connected to the first end of the shaft in the axial direction and having a threaded portion formed at its tip; an impeller having an impeller body formed in the shape of a disc with the axis as the center, and a through hole in the center of the impeller body that penetrates in the axial direction and through which the connecting shaft is inserted; a cylindrical sleeve positioned on the second side in the axial direction opposite to the first side of the impeller, fixed to the shaft so as to cover the shaft on the radially outer side with respect to the axis; and a nut positioned on the first side in the axial direction of the impeller, fastened to the threaded portion to clamp and fix the impeller together with the sleeve in the axial direction, wherein the sleeve end face of the sleeve facing the first side in the axial direction and the impeller end face of the impeller facing the second side in the axial direction are in contact and their positions in the circumferential and radial directions around the axis are constrained from each other.

[0007] The rotating machine according to this disclosure comprises a rotor as described above and a casing that covers the rotor from the radially outer side.

[0008] The rotor assembly method according to the present disclosure is a rotor assembly method as described above, comprising the steps of: fixing the sleeve to the shaft; connecting the connecting shaft to the shaft; inserting the connecting shaft into the insertion hole of the impeller from the axial direction, and bringing the impeller end face and the sleeve end face into contact to restrain each other's positions; and fastening the nut to the threaded portion of the connecting shaft. [Effects of the Invention]

[0009] According to the rotor, rotating machine, and rotor assembly method of this disclosure, the impeller and shaft can be firmly restrained in the radial and circumferential directions while improving ease of assembly. [Brief explanation of the drawing]

[0010] [Figure 1] This figure shows a schematic configuration of the rotating machine according to this embodiment. [Figure 2] This is a cross-sectional view showing the configuration of the main parts of the above-mentioned rotating machine. [Figure 3] This is an enlarged cross-sectional view showing the configuration of the end of the rotor of the above-mentioned rotating machine. [Figure 4] This is a perspective view showing the first fitting portion formed in the sleeve of the rotor described above. [Figure 5] This is a view of the first fitting portion as seen from the first side in the axial direction. [Figure 6] This is a side view showing the fit between the first fitting portion and the second fitting portion formed on the protruding portion of the impeller. [Figure 7] This is a view of the second fitting portion as seen from the second side in the axial direction. [Figure 8] This flowchart shows the procedure for assembling the rotor according to this embodiment. [Figure 9] This figure shows the process of fixing the sleeve in the rotor assembly method described above. [Figure 10] This diagram shows the process of connecting the connecting shaft in the rotor assembly method described above. [Modes for carrying out the invention]

[0011] The following describes embodiments for carrying out the rotor, rotating machine, and rotor assembly method according to this disclosure, with reference to the attached drawings. However, this disclosure is not limited to these embodiments.

[0012] (Configuration of a geared compressor (rotating machine)) As shown in Figures 1 and 2, the geared compressor (centrifugal compressor) 1 as a rotating machine according to this embodiment mainly comprises a rotor 3, a casing 2 (see Figure 2), a speed-increasing transmission unit 11, a radial bearing 12, and a thrust bearing 17.

[0013] (Rotor configuration) The rotor 3 is rotatable about the axis O with respect to the casing 2. The rotor 3 includes a shaft 5, a connecting shaft 6, a sleeve 7, an impeller 4, a nut 8, and a seal portion 9.

[0014] The shaft 5 extends in the axial direction Da along which the axis O extends. The shaft 5 extends about the axis O. As shown in FIG. 1, the shaft 5 is rotatably supported about the axis O by a pair of radial bearings 12. The pair of radial bearings 12 are arranged at intervals in the axial direction Da. The shaft 5 is restricted from moving in the axial direction Da by a pair of thrust bearings 17. The pair of thrust bearings 17 are arranged on both sides in the axial direction Da with respect to a pinion gear 15, which will be described later, between the pair of radial bearings 12. The pair of radial bearings 12 and the pair of thrust bearings 17 are fixed to the casing 2.

[0015] The shaft 5 is connected to a drive source (not shown) such as an external motor via a speed increasing transmission unit 11. The speed increasing transmission unit 11 includes a pinion gear 15 and a large-diameter gear 16. The pinion gear 15 is fixed to the shaft 5 between the pair of radial bearings 12. The large-diameter gear 16 meshes with the pinion gear 15. The large-diameter gear 16 is rotationally driven by the drive source. The outer diameter dimension of the large-diameter gear 16 is set larger than that of the pinion gear 15. Therefore, the rotational speed of the shaft 5 to which the pinion gear 15 is fixed becomes larger than the rotational speed of the large-diameter gear 16. That is, the speed increasing transmission unit 11 increases the rotational speed of the large-diameter gear 16 by the external drive source and transmits it to the shaft 5 via the pinion gear 15.

[0016] The connecting shaft 6, sleeve 7, impeller 4, and nut 8 are respectively arranged at both ends of the shaft 5 in the axial direction Da. That is, the shaft 5 is the longest elongated member in the axial direction Da in the rotor 3. In the following description, in the geared compressor 1, the side close to the ends of the shaft 5 on both sides in the axial direction Da is defined as the first side Da1 in the axial direction Da, and the side away from the ends on both sides in the axial direction Da (the side close to the pinion gear 15, the side close to the central portion of the shaft 5) is defined as the second side Da2 in the axial direction Da. That is, with respect to the pinion gear 15, at one end and the other end of the shaft 5 in the axial direction Da, the first side Da1 and the second side Da2 in the axial direction Da are opposite to each other.

[0017] As shown in FIGS. 2 and 3, the shaft 5 has an insertion hole 52 into which the connecting shaft 6 is inserted. The insertion hole 52 is formed at the end 5a of the shaft 5 on the first side Da1 in the axial direction Da. The insertion hole 52 is recessed from the axial end face 5s facing the first side Da1 in the axial direction Da at the end 5a of the shaft 5 toward the second side Da2 in the axial direction Da around the axis O. The insertion hole 52 is recessed around the axis O from the axial end face 5s. A female screw portion 521 is formed on the inner peripheral surface of the insertion hole 52.

[0018] The shaft 5 has a hole forming portion 50A having the insertion hole 52 and a solid portion 50B formed on the second side Da2 in the axial direction Da with respect to the hole forming portion 50A. The hole forming portion 50A having the insertion hole 52 is formed in a cylindrical shape extending in the axial direction Da around the axis O. The solid portion 5OB has no insertion hole 52 formed therein and is formed in a solid cylindrical shape extending in the axial direction Da around the axis O. In the present embodiment, the hole forming portion 50A and the solid portion 50B are integrally formed with their outer peripheral surfaces smoothly connected.

[0019] The connecting shaft 6 is connected to the end 5a of the first side Da1 of the axial direction Da of the shaft 5. In this embodiment, the connecting shaft 6 forms the end of the rotor 3. The connecting shaft 6 is formed to be much shorter in axial direction Da than the shaft 5. The connecting shaft 6 integrally comprises a shaft body 61, an insertion shaft portion 62, a threaded portion 63, and a flange portion 64.

[0020] The shaft body 61 extends in the axial direction Da with axis O as its center. The shaft body 61 is formed as a cylindrical member with a smaller diameter than the shaft 5. The shaft body 61 is formed in the axial direction Da at a position that overlaps with the impeller 4, which will be described later.

[0021] The insertion shaft portion 62 is formed on the second side Da2 in the axial direction Da relative to the shaft body 61. The insertion shaft portion 62 extends from the shaft body 61 to the second side Da2 in the axial direction Da. The insertion shaft portion 62 is formed as a cylindrical member with a smaller diameter than the shaft body 61 and centered on an axis O. On the outer circumferential surface of the insertion shaft portion 62, facing outward in the radial direction Dr with respect to the axis O, a male threaded portion 621 is formed. The male threaded portion 621 of the insertion shaft portion 62 is fastened by screwing it into the female threaded portion 521 of the insertion hole 52. In this way, the connecting shaft 6 is connected to the end portion 5a of the shaft 5.

[0022] The flange portion 64 is formed to expand in diameter outward in the radial direction Dr from the outer circumferential surface of the insertion shaft portion 62. The flange portion 64 is formed on the first side Da1 in the axial direction Da, adjacent to the connection position with the insertion shaft portion 62. The flange portion 64 extends continuously in the circumferential direction around the axis O, and is formed in a disc shape when viewed from the axial direction Da. With the male threaded portion 621 fastened to the female threaded portion 521, the flange portion 64 is formed in a position that contacts the shaft end face 5s of the shaft 5. In other words, the flange portion 64 abuts against the shaft end face 5s of the shaft 5 from the first side Da1 in the axial direction Da.

[0023] The threaded portion 63 is formed at the tip of the first side Da1 in the axial direction Da of the connecting shaft 6. The threaded portion 63 extends from the shaft body 61 to the first side Da1 in the axial direction Da. The threaded portion 63 has a male screw groove on its outer circumferential surface facing outward Dr in the radial direction Dr.

[0024] The sleeve 7 is positioned on the second side Da2 in the axial direction Da relative to the impeller 4. The sleeve 7 is positioned at the end 5a of the first side Da1 in the axial direction Da of the shaft 5. The sleeve 7 is positioned on the outer side Dro in the radial direction Dr relative to the shaft 5. The sleeve 7 is formed to be much shorter in the axial direction Da than the shaft 5. In this embodiment, it is preferable that the sleeve 7 is formed to be about the same length as or smaller than the connecting shaft 6 in the axial direction Da. The sleeve 7 is formed in a cylindrical shape that extends in the circumferential direction Dc and is large enough to accommodate the shaft 5 inside. The sleeve 7 is fixed to the shaft 5 in a non-movable state while covering the shaft 5. The sleeve 7 is fitted to the outer surface of the shaft 5 by shrink fitting. The sleeve 7 and the shaft 5 are fitted by shrink fitting only at position B where they overlap with the solid portion 50B in the axial direction Da. The sleeve 7 has a sleeve end face 72.

[0025] The sleeve end face 72 is formed at the end of the first side Da1 in the axial direction Da of the sleeve 7. The sleeve end face 72 faces the first side Da1 in the axial direction Da. A first fitting portion 73, which will be described later, is formed on the sleeve end face 72.

[0026] The impeller 4 is positioned immovably on the shaft 5, connecting shaft 6, sleeve 7, and nut 8. The impeller 4 is not directly fixed to the shaft 5 and connecting shaft 6. The impeller 4 in this embodiment has an impeller body 40, an insertion hole 46, and a protruding portion 47 integrated into one unit.

[0027] The impeller body 40 is formed in a disc shape centered on axis O. In this embodiment, the impeller body 40 is a so-called open impeller comprising a disc 41 and blades 42. The impeller body 40 may also be a closed impeller having a cover.

[0028] The disk 41 is disc-shaped and has a first disk surface 41a facing the first side Da1 in the axial direction Da, and a second disk surface 41b facing the opposite side from the first disk surface 41a in the axial direction Da. The second disk surface 41b is the back surface of the impeller body 40. The impeller body 40 is positioned so that the second disk surface 41b, which is the back surface, faces the second side Da2 in the axial direction Da. In other words, as shown in Figure 1, the disks 41 of the first stage impeller 4A provided at the first end of the shaft 5 and the second stage impeller 4B provided at the second end of the shaft 5 are positioned with their back surfaces facing each other in the axial direction Da.

[0029] As shown in Figure 3, the blades 42 extend from the first disk surface 41a. Multiple blades 42 are arranged at intervals in the circumferential direction Dc around the axis O.

[0030] The working fluid (e.g., ammonia gas, air, or hydrogen gas) flows through the impeller body 40 from the first side Da1 in the axial direction Da to the second side Da2 in the axial direction Da. Each impeller body 40 has an impeller flow path 44 formed between the first disk surface 41a of the disk 41 and a plurality of blades 42. The impeller flow path 44 has an inlet 44i and an outlet 44o. The inlet 44i is located in the impeller body 40 at the first side Da1 in the axial direction Da and the inner Dri in the radial direction Dr, and opens toward the first side Da1 in the axial direction Da. Here, the radial direction Dr is the direction centered on the axis O. The outlet 44o is located in the impeller body 40 at the second side Da2 in the axial direction Da and the outer Dro in the radial direction Dr, and opens toward the outer Dro in the radial direction Dr.

[0031] The through hole 46 is formed in the impeller body 40 in the axial direction Da through which the connecting shaft 6 is inserted. The through hole 46 is a through hole formed in the center of the impeller body 40, centered on the axis O. The through hole 46 has a first hole portion 461 formed on the first side Da1 in the axial direction Da, and a second hole portion 462 formed on the second side Da2 in the axial direction Da relative to the first hole portion 461. The inner diameter of the first hole portion 461 is set to be slightly larger than the outer diameter of the shaft body 61 of the connecting shaft 6 so that a predetermined gap in the radial direction Dr is formed between the first hole portion 461 and the shaft body 61. The inner diameter of the second hole portion 462 is set to be larger than the inner diameter of the first hole portion 461. In other words, the radial direction Dr gap formed between the second hole portion 462 and the shaft body 61 is larger than the radial direction Dr gap formed between the first hole portion 461 and the shaft body 61.

[0032] The projection 47 protrudes from the second disk surface 41b to the second side Da2 in the axial direction Da. The projection 47 is formed in a cylindrical shape centered on the axis O. The projection 47 is formed integrally with the impeller body 40. The inner diameter of the projection 47 is the same as that of the second hole 462. As a result, the projection 47 is formed with a gap between it and the connecting shaft 6 and the shaft 5, on the outer side Dro in the radial direction Dr. The projection 47 has an impeller end face 471.

[0033] The impeller end face 471 is formed at the end of the second side Da2 in the axial direction Da of the protruding portion 47. The impeller end face 471 faces the second side Da2 in the axial direction Da. A second fitting portion 48, which will be described later, is formed on the impeller end face 471.

[0034] In this configuration, the impeller 4 and sleeve 7 are in contact with each other at the axial direction Da, with the impeller end face 471 and the sleeve end face 72 being in contact. The sleeve end face 72 and the impeller end face 471 are constrained to each other in the circumferential direction Dc and the radial direction Dr while in contact with each other.

[0035] Furthermore, the first fitting portion 73 and the second fitting portion 48 are formed to fit together while their positions in the circumferential direction Dc and radial direction Dr are constrained to each other. As shown in Figures 4 to 6, the first fitting portion 73 is formed on the sleeve 7 to protrude or recess in the axial direction Da with respect to the surface facing the first side Da1 in the axial direction Da. The first fitting portion 73 in this embodiment has a plurality of first convex portions 731 that protrude in the axial direction Da from the sleeve end face 72 and first recesses 732 that recess in the axial direction Da (eight of each in this embodiment). When viewed from the axial direction Da, the first fitting portion 73 is located outside the radial direction Dr with respect to the axis O and forms an annular region on the sleeve end face 72 centered on the axis O.

[0036] The first protrusions 731 and first recesses 732 are arranged alternately in the circumferential direction Dc centered on the axis O when viewed from the axial direction Da. The first protrusions 731 project from the sleeve end face 72 toward the first side Da1 in the axial direction Da. Multiple first protrusions 731 are arranged at equal distances in the circumferential direction Dc. The first protrusions 731 fit into the second recess 482 of the impeller 4, which will be described later, in a manner that restricts each other's movement in the circumferential direction Dc. The first recesses 732 are recessed toward the second side Da2 in the axial direction Da relative to the first protrusions 731. Multiple first recesses 732 are arranged at equal distances in the circumferential direction Dc. The first recesses 732 fit into the second protrusion 481 of the impeller 4 in a manner that restricts each other's movement in the circumferential direction Dc and radial direction Dr.

[0037] Furthermore, the first fitting portion 73 has a plurality of first surfaces 733, a plurality of first separating surfaces 734, and a plurality of first connecting surfaces 735. The plurality of first surfaces 733, the plurality of first separating surfaces 734, and the plurality of first connecting surfaces 735 form a plurality of first protrusions 731 and first recesses 732.

[0038] Multiple first surfaces 733 are arranged at equal intervals in the circumferential direction Dc. Each first surface 733 is a plane facing the first side Da1 in the axial direction Da. Each first surface 733 is the top surface of the first protrusion 731, located at the firstmost Da1 in the axial direction Da.

[0039] The first separation surface 734 is positioned away from the first surface 733 in the circumferential direction Dc, so as to be staggered relative to the first surface 733 when viewed from the axial direction Da. The first separation surface 734 is formed at a position offset from the first surface 733 in the axial direction Da. In this embodiment, the first separation surface 734 is formed at a position offset from the first surface 733 to the second side Da2 in the axial direction Da. The first separation surface 734 is a plane facing the first side Da1 in the axial direction Da. The first separation surface 734 is the bottom surface located at the second side Da2 in the axial direction Da of the first recess 732.

[0040] The first connecting surface 735 is positioned between adjacent first surfaces 733 and first separating surfaces 734 in the circumferential direction Dc. Multiple first connecting surfaces 735 are positioned at intervals in the circumferential direction Dc. Each first connecting surface 735 connects to a first surface 733 and a first separating surface 734. In this embodiment, the first connecting surface 735 is formed as a plane such that, when viewed from the axial direction Da, the connection lines to the first surface 733 and the connection lines to the first separating surfaces 734 are straight lines extending radially in the radial direction Dr with respect to the axis O. In other words, the first connecting surface 735 is an inclined surface that extends straight in the radial direction Dr, facing the axial direction Da and the circumferential direction Dc.

[0041] A first protrusion 731 is formed by a first surface 733 and two first connecting surfaces 735 positioned on both sides of the first surface 733 in the circumferential direction Dc. A first recess 732 is formed by a first separating surface 734 and two first connecting surfaces 735 positioned on both sides of the first separating surface 734 in the circumferential direction Dc.

[0042] When viewed from the radial direction Dr, the first connecting surface 735 widens in the circumferential direction Dc, moving away from the first surface 733 as it moves from the first side Da1 to the second side Da2 in the axial direction Da. As a result, the distance between the first connecting surfaces 735 located on both sides of the circumferential direction Dc in the first protrusion 731 gradually widens from the first side Da1 to the second side Da2 in the axial direction Da when viewed from the radial direction Dr. Similarly, the distance between the first connecting surfaces 735 located on both sides of the circumferential direction Dc in the first recess 732 gradually narrows from the first side Da1 to the second side Da2 in the axial direction Da when viewed from the radial direction Dr.

[0043] In the first fitting portion 73, the first surface 733, the first connecting surface 735, the first separating surface 734, the first connecting surface 735, and the first surface 733 are repeatedly arranged in the circumferential direction Dc in that order, forming multiple first convex portions 731 and first concave portions 732 in a shape similar to a hearth coupling.

[0044] As shown in Figures 6 and 7, the second fitting portion 48 is formed on the impeller 4 so as to protrude or recess in the axial direction Da with respect to the surface facing the second side Da2 in the axial direction Da. The second fitting portion 48 in this embodiment has a plurality of second convex portions 481 that protrude in the axial direction Da from the impeller end face 471 and a plurality of second recesses 482 that recess in the axial direction Da (eight of each in this embodiment). When viewed from the axial direction Da, the second fitting portion 48 is located outside the radial direction Dr with respect to the axis O and forms an annular region on the impeller end face 471 centered on the axis O. When viewed from the axial direction Da, the second fitting portion 48 is formed in a position that overlaps with the first fitting portion 73.

[0045] The second protrusions 481 and second recesses 482 are arranged alternately in the circumferential direction Dc centered on the axis O when viewed from the axial direction Da. The second protrusions 481 project from the impeller end face 471 to the second side Da2 in the axial direction Da. Multiple second protrusions 481 are arranged at equal distances in the circumferential direction Dc. The second protrusions 481 are positioned to overlap with the first recesses 732 when viewed from the axial direction Da. The second recesses 482 are recessed to the first side Da1 in the axial direction Da relative to the second protrusions 481. Multiple second recesses 482 are arranged at equal distances in the circumferential direction Dc. The second recesses 482 are positioned to overlap with the first protrusions 731 when viewed from the axial direction Da.

[0046] Furthermore, the second fitting portion 48 has a plurality of second surfaces 483, a plurality of second separating surfaces 484, and a plurality of second connecting surfaces 485. The plurality of second surfaces 483, a plurality of second separating surfaces 484, and a plurality of second connecting surfaces 485 form a plurality of second protrusions 481 and second recesses 482.

[0047] The second surface 483 is a plane facing the second side Da2 in the axial direction Da. When viewed from the axial direction Da, the second surface 483 is formed to be the same size as the first surface 733. Also, when viewed from the axial direction Da, the second surface 483 is positioned to overlap with the first surface 733. In the second recess 482, the second surface 483 is the bottom surface located at the first side Da1 in the axial direction Da.

[0048] The second separation surface 484 is positioned away from the second surface 483 in the circumferential direction Dc, so as to be staggered relative to the second surface 483 when viewed from the axial direction Da. The second separation surface 484 is formed at a position offset from the second surface 483 in the axial direction Da. In this embodiment, the second separation surface 484 is formed at a position offset from the second surface 483 in the axial direction Da to the second side Da2. The second separation surface 484 is a plane facing the second side Da2 in the axial direction Da. When viewed from the axial direction Da, the second separation surface 484 is formed to be smaller than the second surface 483. When viewed from the axial direction Da, the second separation surface 484 is formed to be the same size as the first separation surface 734. The second separation surface 484 is the apex surface of the second protrusion 481, located at the second side Da2 in the axial direction Da. When viewed from the axial direction Da, the second separation surface 484 is positioned to overlap with the first separation surface 734.

[0049] The second connecting surface 485 is positioned between adjacent second surfaces 483 and second separating surfaces 484 in the circumferential direction Dc. Multiple second connecting surfaces 485 are arranged at intervals in the circumferential direction Dc. Each second connecting surface 485 connects to the second surface 483 and the second separating surface 484. In this embodiment, the second connecting surface 485 is formed as a plane such that, when viewed from the axial direction Da, the connection lines to the second surface 483 and the connection lines to the second separating surface 484 are straight lines extending radially in the radial direction Dr centered on the axis O. In other words, the second connecting surface 485 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 485 is positioned to overlap with the first connecting surface 735 when viewed from the axial direction Da. The second connecting surface 485 is formed to be the same size as the first connecting surface 735 when viewed from the axial direction Da.

[0050] A second recess 482 is formed by the second surface 483 and two second connecting surfaces 485 positioned on both sides of the second surface 483 in the circumferential direction Dc. A second convex portion 481 is formed by the second separating surface 484 and two second connecting surfaces 485 positioned on both sides of the second separating surface 484 in the circumferential direction Dc. Therefore, in the second fitting portion 48, the order of the second convex portion 481 and the second recess 482 in the circumferential direction Dc is the reverse of the order of the first convex portion 731 and the first recess 732 in the circumferential direction Dc of the first fitting portion 73.

[0051] When viewed from the radial direction Dr, the second connecting surface 485 widens in the circumferential direction Dc, moving away from the second surface 483 as it moves from the first side Da1 to the second side Da2 in the axial direction Da. As a result, the distance between the second connecting surfaces 485 located on both sides of the circumferential direction Dc in the second protrusion 481 gradually narrows when viewed from the radial direction Dr, moving from the first side Da1 to the second side Da2 in the axial direction Da. Similarly, the distance between the second connecting surfaces 485 located on both sides of the circumferential direction Dc in the second recess 482 gradually widens when viewed from the radial direction Dr, moving from the first side Da1 to the second side Da2 in the axial direction Da.

[0052] In the second fitting portion 48, the second surface 483, second connecting surface 485, second separating surface 484, second connecting surface 485, and second surface 483 are repeatedly arranged in the circumferential direction Dc in that order, thereby forming multiple second recesses 482 and second protrusions 481 in a shape similar to a hearth coupling.

[0053] As the second fitting portion 48 and the first fitting portion 73 fit together, the sleeve end face 72 and the impeller end face 471 are constrained in terms of their positions in the circumferential direction Dc and radial direction Dr.

[0054] Furthermore, when the first fitting portion 73 and the second fitting portion 48 are fitted together, the first connecting surface 735 and the second connecting surface 485 are in contact. The first surface 733 and the second surface 483, and the first separating surface 734 and the second separating surface 484 may be in contact with each other in the axial direction Da, or they may be facing each other with a gap in the axial direction Da. Multiple first connecting surfaces 735 only need to be in contact with at least some of the multiple second connecting surfaces 485.

[0055] As shown in Figure 3, the nut 8 is positioned on the first side Da1 in the axial direction Da relative to the impeller 4. The nut 8 fastens to the threaded portion 63 of the connecting shaft 6, thereby sandwiching and fixing the impeller 4 together with the sleeve 7 in the axial direction Da. The nut 8 is formed in a disc shape centered on the axis O. The inner circumferential surface of the nut 8 has a female thread groove that engages with the male thread groove of the threaded portion 63. The outer circumferential surface of the nut 8 is positioned inward Dri in the radial direction Dr relative to the first disc surface 41a so as not to obstruct the flow of working fluid into the impeller passage 44. The axial length Da of the nut 8 is formed to be shorter than the threaded portion 63 so that the end face of the threaded portion 63, which is the tip of the connecting shaft 6, protrudes. By fastening the nut 8 to the threaded portion 63, the nut 8 is fixed to the threaded portion 63 in the axial direction Da, pressing the impeller 4 toward the sleeve 7.

[0056] The seal portion 9 seals the space between the outer circumferential surface of the shaft 5 and the inner circumferential surface of the sleeve 7. In this embodiment, the seal portion 9 has, for example, a seal member 91 positioned on the outer side of the flange portion 64 of the connecting shaft 6 in the radial direction Dr. The seal member 91 is positioned on the outer side of the flange portion 64 of the connecting shaft 6 in the radial direction Dr. The seal member 91 is held in a groove formed on the outer circumferential surface of the flange portion 64 facing the outer side of the radial direction Dr. The seal member 91 extends in the circumferential direction Dc and is formed in an annular shape when viewed from the axial direction Da. The seal member 91 is, for example, an O-ring made of an elastically deformable rubber material. The seal member 91 slides against the inner circumferential surface 7f of the sleeve 7 facing the inner side of the radial direction Dri. As a result, the seal portion 9 seals the space between the outer circumferential surface of the flange portion 64 and the inner circumferential surface 7f of the sleeve 7. Therefore, the seal portion 9 indirectly prevents the working fluid compressed by the impeller 4 from passing through the gap between the flange portion 64 and the sleeve 7 and reaching the gap between the outer circumferential surface of the shaft 5 located at the second side Da2 in the axial direction Da and the inner circumferential surface of the sleeve 7.

[0057] (Casing configuration) As shown in Figure 2, the casing 2 is formed to cover the rotor 3. The casing 2 is made of metal and forms the outer shell of the geared compressor 1. The casing 2 has shaft insertion holes 21 on the second side Da2 in the axial direction Da with respect to the position where the impeller body 40 is arranged, through which the shaft 5 and sleeve 7 are inserted. The casing 2 has intake nozzles 22 and exhaust passages 23 around each impeller body 40.

[0058] The intake nozzle 22 introduces working fluid into the casing 2. The intake nozzle 22 is formed in a cylindrical shape so as to extend in the axial direction Da. Inside the intake nozzle 22, there is a suction port 22a centered on the axis O. The intake nozzle 22 communicates with the outside of the casing 2 and the inlet 44i of the impeller flow path 44, which opens in the inner Dri in the radial direction Dr of the impeller body 40, through the suction port 22a. As the impeller body 40 rotates in the circumferential direction Dc around the axis O, working fluid is drawn into the casing 2 from the outside through the suction port 22a.

[0059] The exhaust passage 23 allows the working fluid inside the casing 2 to flow out of the casing 2. The exhaust passage 23 is formed on the outer side of the outlet 44o of the impeller passage 44 in the radial direction Dr. The exhaust passage 23 has a spiral shape that is continuous in the circumferential direction Dc.

[0060] In such a geared compressor 1, the working fluid is drawn into the intake nozzle 22 of the casing 2 from the intake port 22a as the impeller body 40 rotates integrally with the shaft 5. The working fluid is taken into the impeller passage 44 from the intake nozzle 22 through the inlet 44i. The working fluid flows from the inlet 44i to the outlet 44o due to the centrifugal force generated by the impeller body 40 rotating integrally with the shaft 5. The working fluid is compressed as it flows from the inlet 44i to the outlet 44o. The compressed working fluid flows out from the outlet 44o to the outer Dro in the radial direction Dr and is sent to the exhaust passage 23 on the outer Dro in the radial direction Dr. The working fluid is further compressed as it swirls around the axis O along the exhaust passage 23.

[0061] (Rotor assembly procedure) Next, as shown in Figure 8, the assembly method S10 of the rotor 3 according to this embodiment will be described. The assembly method S10 of the rotor 3 includes the steps of fixing the sleeve 7 in step S11, connecting the connecting shaft 6 in step S12, setting the impeller 4 in step S13, and fastening the nut 8 in step S14.

[0062] In step S11, where the sleeve 7 is fixed, the sleeve 7 is fixed to the shaft 5 as shown in Figure 9. The sleeve 7 is fitted onto the shaft 5 by shrink fitting. The sleeve 7 is shrink-fitted so that the sleeve 7 and the shaft 5 are fitted together at position B where they overlap with the solid portion 50B in the axial direction Da.

[0063] In step S12, where the connecting shaft 6 is connected, the connecting shaft 6 is connected to the shaft 5 as shown in Figure 10. Specifically, the insertion shaft portion 62 is inserted into the insertion hole 52 while the male threaded portion 621 is screwed into the female threaded portion 521. At this time, a sealing member 91 is fixed to the outer circumferential surface of the flange portion 64 of the connecting shaft 6. Subsequently, the insertion shaft portion 62 is inserted into the insertion hole 52 until the flange portion 64 contacts the shaft end face 5s of the shaft 5 from the first side Da1 in the axial direction Da. In this state, the male threaded portion 621 is fastened to the female threaded portion 521, so the connecting shaft 6 is fixed to the shaft 5 in a state where it cannot move in the axial direction Da.

[0064] In step S13, when the impeller 4 is set, as shown in Figure 3, the impeller 4 is moved relative to the shaft 5 so that the connecting shaft 6 is inserted into the insertion hole 46 from the second side Da2 in the axial direction Da. The connecting shaft 6 is inserted into the insertion hole 46 until the impeller end face 471 and the sleeve end face 72 are in contact. The sleeve end face 72 and the impeller end face 471 are brought into contact with each other with the first fitting portion 73 and the second fitting portion 48 fitted together. As a result, the circumferential Dc and radial Dr positions of the impeller 4 and the sleeve 7 fixed to the shaft 5 are constrained from each other. In other words, the impeller 4 is made immobile relative to the shaft 5 in the circumferential Dc and radial Dr directions. Furthermore, when the impeller end face 471 and the sleeve end face 72 are in contact, the screw portion 63 protrudes from the impeller 4 toward the first side Da1 in the axial direction Da.

[0065] In step S14, where the nut 8 is fastened, the nut 8 is fastened to the threaded portion 63. The threaded portion 63 of the nut 8 is inserted to a position where it presses the impeller 4 toward the sleeve 7 in the axial direction Da. In this state, the male thread groove of the threaded portion 63 and the female thread groove of the nut 8 are screwed together, fixing the nut 8 in a state where it cannot move relative to the threaded portion 63. As a result, the nut 8, together with the sleeve 7, clamps and fixes the impeller 4 in the axial direction Da. Therefore, the impeller 4 is fixed in a state where it cannot move in the axial direction Da, the circumferential direction Dc, and the radial direction Dr relative to the shaft 5, the connecting shaft 6, the sleeve 7, and the nut 8. In this way, the assembly of the rotor 3 is completed.

[0066] (Effects and Benefits) In the rotor 3 and rotating machine 1 configured as described above, the impeller 4 is positioned with a connecting shaft 6, which is connected to the end 5a of the shaft 5, inserted through the insertion hole 46. In this state, the impeller 4 is sandwiched and fixed in the axial direction Da by a cylindrical sleeve 7 positioned to cover the shaft 5 and a nut 8 fastened to the threaded portion 63 of the connecting shaft 6. As a result, with the impeller end face 471 and the sleeve end face 72 in contact, the impeller 4 is fixed in a state where it cannot move in the axial direction Da, circumferential direction Dc, and radial direction Dr relative to the shaft 5, connecting shaft 6, sleeve 7, and nut 8. More specifically, the positions in the circumferential direction Dc and radial direction Dr are constrained by only the contact between the sleeve end face 72 of the sleeve 7 facing the first side Da1 and the impeller end face 471 of the impeller 4 facing the second side Da2 of the axial direction Da. Furthermore, the sleeve 7 is fixed to the shaft 5 by shrink fitting. As a result, the impeller 4 is constrained in the circumferential direction Dc and radial direction Dr relative to the shaft 5. In this state, by fastening the nut 8 to the threaded portion 63, the impeller 4 is sandwiched between the sleeve 7 and the nut 8, making it impossible to move in the axial direction Da. In other words, by simply attaching the nut 8, the impeller 4 can be easily attached to the shaft 5 while remaining movable. Therefore, the impeller 4 and the shaft 5 can be firmly restrained in the radial direction Dr and circumferential direction Dc while improving ease of assembly.

[0067] Furthermore, the shaft 5, to which the pinion gear 15 that meshes with the large-diameter gear 16 is fixed, is formed as a separate component from the connecting shaft 6, sleeve 7, and nut 8. Therefore, there is no need to form a structure on the shaft 5 for fixing the impeller 4. Consequently, treatments to increase the tooth surface strength of the pinion gear 15, such as carburizing, can be applied to the shaft 5 without affecting the mounting of the impeller 4.

[0068] Furthermore, the movement of the sleeve 7 and the impeller 4 in the circumferential direction Dc is mutually restricted by the multiple first fitting portions 73 and second fitting portions 48 arranged in the circumferential direction Dc. In addition, the first fitting portion 73 has a first convex portion 731 and a first recess 732, and the second fitting portion 48 has a second convex portion 481 and a second recess 482. The movement of the sleeve 7 and the impeller 4 in the circumferential direction Dc and radial direction Dr is mutually restricted simply by the fitting of the first convex portion 731 and the second recess 482, and the fitting of the first recess 732 and the second convex portion 481. Therefore, the position of the impeller 4 in the radial direction Dr relative to the sleeve 7 can be aligned before the position is completely fixed with the nut 8. As a result, the centering of the impeller 4 relative to the shaft 5 can be easily performed. In this way, the workability when assembling the rotor 3 is improved, and the relative positions of the sleeve end face 72 and the impeller end face 471 can be easily restrained.

[0069] Furthermore, the first fitting portion 73, which fits into the second fitting portion 48 formed on the impeller 4, is formed on the sleeve 7, not the shaft 5. Therefore, there is no need to form the first fitting portion 73 on the long shaft 5, which reduces the effort required to process the shaft 5. Also, when forming the first fitting portion 73, the sleeve 7 can be processed as a standalone unit. Therefore, compared to forming the first fitting portion 73 on the shaft 5, the work efficiency of the processing work can be improved. Moreover, if the first fitting portion 73 is damaged, the sleeve 7 can be replaced as a standalone unit instead of the shaft 5, improving the maintainability of the rotor 3.

[0070] Furthermore, in the sleeve 7, a first protrusion 731 is formed by the first surface 733 and the first connecting surfaces 735 located on both sides of the first surface 733 in the circumferential direction Dc. Also, a first recess 732 is formed by the first separating surface 734 and the first connecting surfaces 735 located on both sides of the first separating surface 734 in the circumferential direction Dc. Similarly, in the impeller 4, a second protrusion 481 is formed by the second separating surface 484 and the second connecting surfaces 485 located on both sides of the second separating surface 484 in the circumferential direction Dc. A second recess 482 is formed by the second surface 483 and the second connecting surfaces 485 located on both sides of the second surface 483 in the circumferential direction Dc. When the sleeve end surface 72 and the impeller end surface 471 are in contact, the multiple first connecting surfaces 735 contact at least a portion of the multiple second connecting surfaces 485. In other words, the first protrusion 731 and the second recess 482, and the first recess 732 and the second protrusion 481, are immobilized in the circumferential direction Dc by the first connecting surface 735 and the second connecting surface 485. Therefore, the radial position Dr of the impeller 4 can be aligned more accurately before the position is completely fixed with the nut 8. As a result, the centering of the impeller 4 relative to the shaft 5 can be performed easily with high precision. This greatly improves the workability when assembling the rotor 3.

[0071] Furthermore, when viewed from the radial direction Dr, the multiple first connecting surfaces 735 widen in the circumferential direction Dc, moving away from the first surface 733 as they move from the first side Da1 to the second side Da2 in the axial direction Da. As a result, in the first protrusion 731, the spacing between the first connecting surfaces 735 located on both sides of the first surface 733 in the circumferential direction Dc widens as they approach the first separating surface 734. Similarly, in the second protrusion 481, the spacing between the second connecting surfaces 485 located on both sides of the second surface 483 in the circumferential direction Dc widens as they approach the second separating surface 484. Therefore, when assembling the rotor 3 and bringing the impeller 4 closer to the sleeve 7, the insertion of the first protrusion 731 into the second recess 482 and the insertion of the second protrusion 481 into the first recess 732 are guided by the first connecting surfaces 735 and the second connecting surfaces 485. Therefore, even if the circumferential Dc and radial Dr positions of the impeller 4 are misaligned with respect to the sleeve 7, the first connection surface 735 and the second connection surface 485 correct the positions in the circumferential Dc and radial Dr directions. This allows the impeller 4 to be easily assembled to the sleeve 7. Consequently, the ease of assembly of the rotor 3 can be further improved.

[0072] Furthermore, the multiple first connecting surfaces 735 and the multiple second connecting surfaces 485 are formed as planes such that the connection lines with other surfaces are straight. As a result, the first surface 733 and the first separating surface 734 are connected by the first connecting surface 735, which is a plane. Similarly, the second surface 483 and the second separating surface 484 are connected by the second connecting surface 485, which is a plane. In other words, the first convex portion 731 and the first concave portion 732, and the second convex portion 481 and the second concave portion 482 are formed in a shape similar to a hearth coupling. Therefore, the first connecting surface 735 and the second connecting surface 485 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 735 and the second connecting surface 485, and improves the workability when processing the first fitting portion 73 and the second fitting portion 48.

[0073] Furthermore, the second fitting portion 48 is formed on a protruding portion 47 that extends from the impeller body 40. This allows the second fitting portion 48 to be formed without being affected by the shape of the impeller body 40. In addition, by forming the second fitting portion 48 on the protruding portion 47, the processing of the second convex portion 481 and the second concave portion 482 can be made easier during the manufacturing of the impeller 4 compared to when the second fitting portion 48 is formed on the impeller body 40. As a result, a decrease in the strength of the impeller body 40 and processing limitations on the shape of the second fitting portion 48 can be suppressed. Also, because the second fitting portion 48 is formed in a position that protrudes from the impeller body 40, the contact state between the first fitting portion 73 and the second fitting portion 48 can be easily confirmed by visual inspection.

[0074] Furthermore, the protrusion 47 is formed with a gap between it and the connecting shaft 6 and the shaft 5, on the outer side of the radial direction Dr. This means that the thickness of the protrusion 47 in the radial direction Dr can be reduced. As a result, the rigidity of the protrusion 47 is lower compared to the impeller body 40. When the impeller 4 rotates in the circumferential direction Dc together with the shaft 5 and the connecting shaft 6, centrifugal force acts on the impeller 4. This centrifugal force can cause deformation and displacement in the impeller body 40 and the protrusion 47, which may spread outwards on the outer side of the radial direction Dr. On the other hand, at the impeller end face 471, the deformation and displacement due to centrifugal force are restricted because the second fitting portion 48 is fitted with the first fitting portion 73. In this state, the reduced rigidity of the protrusion 47 allows the deformation and displacement of the protrusion 47 due to centrifugal force to be suppressed so as to follow the restricted impeller end face 471. Therefore, the influence of centrifugal force acting on the impeller 4 on the second fitting portion 48 can be suppressed.

[0075] Furthermore, the sleeve 7 and the shaft 5 are fitted together by shrink fitting. This allows the sleeve 7 to be firmly fixed to the shaft 5 without requiring any prior processing to fix the sleeve 7 to the shaft 5. Therefore, the strength of the rotor 3 can be stabilized while improving the workability of the shaft 5 processing work.

[0076] Furthermore, the sleeve 7 and the shaft 5 are fitted together by shrink fitting. When fitted by shrink fitting, a tightening force acts from the sleeve 7 on the shaft 5 in the radial direction Dr toward the inner Dri. In the shaft 5, the solid part 50B, which has no internal space, is stronger against deformation in the radial direction Dr acting from the sleeve 7 than the hole-forming part 50A, which has an internal space. Therefore, by shrink fitting the sleeve 7 and the shaft 5 at a position B that overlaps with the solid part 50B in the axial direction Da, deformation of the shaft 5 can be suppressed and the sleeve 7 can be firmly fixed to the shaft 5. On the other hand, if the sleeve 7 and shaft 5 are fitted by shrink fitting at a position that overlaps with the hole-forming part 50A, the tightening force from the sleeve 7 may deform the hole-forming part 50A, making it difficult to insert the connecting shaft 6 into the insertion hole 52 in the hole-forming part 50A. In contrast, by shrink-fitting the rotor 3 at position B, which overlaps with the solid portion 50B, deformation of the insertion hole 52 can be suppressed, and the ease of assembly of the rotor 3 can be maintained.

[0077] Furthermore, the sealing member 91 seals the space between the outer circumferential surface of the flange portion 64 and the inner circumferential surface 7f of the sleeve 7. In other words, the sealing portion 9 can suppress the inflow of working fluid into the space between the outer circumferential surface of the shaft 5 and the inner circumferential surface of the sleeve 7. As a result, in a rotating machine 1 equipped with such a rotor 3, when a corrosive gas is used as the working fluid, it is possible to suppress the corrosive gas compressed by the impeller 4 from reaching the shaft 5.

[0078] Furthermore, in the rotor assembly method S10, which includes the shaft 5, connecting shaft 6, sleeve 7, and nut 8 as described above, the impeller 4 and shaft 5 can be firmly restrained in the radial direction Dr and circumferential direction Dc during the assembly of the rotor 3, while improving ease of assembly.

[0079] (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.

[0080] In the above embodiment, the geared compressor 1 was described using a so-called single-shaft, two-stage configuration as an example. However, the configuration of the geared compressor 1 is not limited to this, and it may have two shafts, four stages, or more shafts and stages depending on the design and specifications.

[0081] Furthermore, the rotating machine of the present invention is not limited to the geared compressor 1, but may also be a centrifugal compressor, a gas turbine, a steam turbine, or the like.

[0082] Furthermore, the sleeve 7 is not limited to a structure that is fixed to the shaft 5 by shrink fitting. The sleeve 7 may be fixed to the shaft 5 by other fitting methods such as cold fitting, or by fixing methods using other fixing members such as bolts.

[0083] Furthermore, the multiple first connecting surfaces 735 and the multiple second connecting surfaces 485 are not limited to being planes such that the connection lines with other surfaces are straight. In other words, the first protrusions 731 and first recesses 732 and the second protrusions 481 and second recesses 482 are not limited to being formed in a shape like a hearth coupling. For example, the multiple first connecting surfaces 735 and the multiple second connecting surfaces 485 may be formed as curved surfaces such that the connection lines with other surfaces are curved. In other words, the first protrusions 731 and first recesses 732 and the second protrusions 481 and second recesses 482 may be formed in a shape like a curvilinear coupling.

[0084] Furthermore, the seal portion 9 is not limited to a structure that is arranged on the connecting shaft 6, such as the flange portion 64, and indirectly seals the space between the outer circumferential surface of the shaft 5 and the inner circumferential surface of the sleeve 7. The seal portion 9 may, for example, be directly arranged between the outer circumferential surface of the shaft 5 and the inner circumferential surface of the sleeve 7.

[0085] <Note> The assembly method of the rotor 3, the rotating machine 1, and the rotor 3 described in the embodiment can be understood, for example, as follows.

[0086] (1) The rotor 3 according to the first embodiment includes a shaft 5 extending in the axial direction Da along which the axis O extends, a connecting shaft 6 connected to the end 5a of the first side Da1 of the shaft 5 in the axial direction Da and having a threaded portion 63 formed at its tip, an impeller 4 having an impeller body 40 formed in the shape of a disc with the axis O as its center, and an insertion hole 46 in the center of the impeller body 40 that penetrates in the axial direction Da and through which the connecting shaft 6 is inserted, and a second side Da2 of the axial direction Da opposite to the first side Da1 with respect to the impeller 4, and radially with respect to the shaft 5 with respect to the axis O The outer part of the shaft 5, Dr, includes a cylindrical sleeve 7 fixed to the shaft 5 so as to cover the shaft 5, and a nut 8 positioned on the first side Da1 in the axial direction Da relative to the impeller 4, which is fastened to the threaded portion 63 to sandwich and fix the impeller 4 together with the sleeve 7 in the axial direction Da. The sleeve end face 72 of the sleeve 7 facing the first side Da1 in the axial direction Da and the impeller end face 471 of the impeller 4 facing the second side Da2 in the axial direction Da are in contact, and their positions in the circumferential direction Dc and the radial direction Dr around the axis O are constrained from each other.

[0087] As a result, with the impeller end face 471 and the sleeve end face 72 in contact, the impeller 4 is fixed to the shaft 5, connecting shaft 6, sleeve 7, and nut 8 in a state where it cannot move in the axial direction Da, circumferential direction Dc, and radial direction Dr. More specifically, the positions of the circumferential direction Dc and radial direction Dr are constrained by the contact between the sleeve end face 72 of the sleeve 7 facing the first side Da1 and the impeller end face 471 of the impeller 4 facing the second side Da2 of the axial direction Da. Furthermore, the sleeve 7 is fixed to the shaft 5. As a result, the position of the impeller 4 is constrained in the circumferential direction Dc and radial direction Dr relative to the shaft 5. In this state, by fastening the nut 8 to the threaded portion 63, the impeller 4 is sandwiched between the sleeve 7 and the nut 8, making it impossible to move in the axial direction Da. In other words, by simply attaching the nut 8, the impeller 4 can be easily attached to the shaft 5 in a state where it can move relative to the shaft 5. Therefore, the impeller 4 and the shaft 5 can be firmly restrained in the radial direction Dr and the circumferential direction Dc while improving ease of assembly.

[0088] (2) The rotor 3 according to the second embodiment is the rotor 3 of (1), wherein the sleeve 7 has a first fitting portion 73 formed on the sleeve end face 72, in which a first convex portion 731 protruding in the axial direction Da from a first surface 733 facing the first side Da1 in the axial direction Da and a first recessed portion 732 that is recessed therein are arranged in the circumferential direction Dc, and the impeller 4 has a second fitting portion 48 formed on the impeller end face 471, in which a second convex portion 481 protruding in the axial direction Da from a second surface 483 facing the second side Da2 in the axial direction Da and a second recessed portion 482 that is recessed therein are arranged in the circumferential direction Dc, the first convex portion 731 fits with the second recessed portion 482 in such a way that their movement in the circumferential direction Dc is mutually restricted, and the first recessed portion 732 fits with the second convex portion 481 in such a way that their movement in the circumferential direction Dc is mutually restricted.

[0089] As a result, the first protrusion 731 and the second recess 482 fit together, and the movement of the sleeve 7 and the impeller 4 in the circumferential direction Dc and radial direction Dr is restricted simply by the fitting of the first recess 732 and the second protrusion 481. Therefore, the radial Dr position of the impeller 4 relative to the sleeve 7 can be aligned before the position is completely fixed with the nut 8. As a result, the centering of the impeller 4 relative to the shaft 5 can be easily performed. In this way, the workability when assembling the rotor 3 is improved, and the relative positions of the sleeve end face 72 and the impeller end face 471 can be easily restrained.

[0090] (3) The rotor 3 according to the third embodiment is the rotor 3 of (1) or (2), wherein the first fitting portion 73 has a plurality of first surfaces 733 facing the axial direction Da, a plurality of first separated surfaces 734 that are arranged separately in the circumferential direction Dc so as to be staggered with respect to the first surfaces 733 when viewed from the axial direction Da, and are formed at positions offset in the axial direction Da with respect to the first surfaces 733, and a plurality of first connecting surfaces 735 that are arranged between the first surfaces 733 and the first separated surfaces 734 in the circumferential direction Dc and connect the first surfaces 733 and the first separated surfaces 734, and the second fitting portion 48 is The device has a plurality of second surfaces 483 that are positioned to overlap with the first surface 733 when viewed from the axial direction Da and facing the axial direction Da, a plurality of second separating surfaces 484 that are positioned to overlap with the first separating surface 734 when viewed from the axial direction Da and formed at a position offset in the axial direction Da relative to the second surfaces 483, and a plurality of second connecting surfaces 485 that are positioned to overlap with the first connecting surface 735 when viewed from the axial direction Da and connect the second surfaces 483 and the second separating surfaces 484, wherein the plurality of first connecting surfaces 735 are in contact with at least a portion of the plurality of second connecting surfaces 485.

[0091] As a result, the first protrusion 731 and the second recess 482, and the first recess 732 and the second protrusion 481, are immobilized in the circumferential direction Dc by the first connecting surface 735 and the second connecting surface 485. Therefore, the radial position Dr of the impeller 4 can be aligned more accurately before the position is completely fixed with the nut 8. As a result, the centering of the impeller 4 relative to the shaft 5 can be performed easily with high precision. This greatly improves the workability when assembling the rotor 3.

[0092] (4) The rotor 3 according to the fourth embodiment is the rotor 3 of (3), wherein the first surface 733 is located on the first side Da1 in the axial direction Da with respect to the first separating surface 734 when viewed from the radial direction Dr, and the plurality of first connecting surfaces 735 spread out in the circumferential direction Dc away from the first surface 733 as viewed from the radial direction Dr, from the first side Da1 in the axial direction Da toward the second side Da2.

[0093] As a result, in the first protrusion 731, the distance between the first connecting surfaces 735, which are located on both sides of the first surface 733 in the circumferential direction Dc, widens as it approaches the first separating surface 734. Therefore, when assembling the rotor 3, the insertion of the first protrusion 731 into the second recess 482, and the insertion of the second protrusion 481 into the first recess 732, are guided by the first connecting surfaces 735. Therefore, even if the position of the impeller 4 in the circumferential direction Dc and radial direction Dr is misaligned with respect to the sleeve 7, the position in the circumferential direction Dc and radial direction Dr is corrected by the first connecting surfaces 735. This makes it easy to assemble the impeller 4 to the sleeve 7. Thus, the ease of assembly of the rotor 3 can be further improved.

[0094] (5) The rotor 3 according to the fifth embodiment is the rotor 3 of (2) or (3), wherein the impeller 4 has a protruding portion 47 that protrudes cylindrically from the impeller body 40 to the second side Da2 in the axial direction Da, and the second fitting portion 48 is formed on the protruding portion 47.

[0095] This allows the second fitting portion 48 to be formed without being affected by the shape of the impeller body 40. Therefore, a decrease in the strength of the impeller body 40 and limitations on the shape of the second fitting portion 48 during manufacturing are suppressed. In addition, because the second fitting portion 48 is formed in a position that protrudes from the impeller body 40, it becomes easier to visually confirm the contact state between the first fitting portion 73 and the second fitting portion 48.

[0096] (6) The rotor 3 according to the sixth embodiment is the rotor 3 of (5), wherein the protrusion 47 is formed with a gap between it and the connecting shaft 6 and the shaft 5, on the outer side of the radial Dr.

[0097] This makes it possible to reduce the thickness of the protrusion 47 in the radial direction Dr. As a result, the rigidity of the protrusion 47 is lower compared to the impeller body 40. When the impeller 4 rotates in the circumferential direction Dc together with the shaft 5 and the connecting shaft 6, centrifugal force acts on the impeller 4. This centrifugal force can cause deformation and displacement of the impeller body 40 and the protrusion 47, which may spread outward in the radial direction Dr Dro. On the other hand, at the impeller end face 471, the deformation and displacement due to centrifugal force are restricted because the second fitting portion 48 is fitted with the first fitting portion 73. In this state, the reduced rigidity of the protrusion 47 allows the deformation and displacement of the protrusion 47 due to centrifugal force to be suppressed so as to follow the restricted impeller end face 471. Therefore, the influence of the centrifugal force acting on the impeller 4 on the second fitting portion 48 can be suppressed.

[0098] (7) The rotor 3 according to the seventh embodiment is any one of the rotors 3 from (1) to (6), wherein the sleeve 7 and the shaft 5 are fitted together by shrink fitting.

[0099] This allows the sleeve 7 to be firmly fixed to the shaft 5 without requiring any prior processing to secure the sleeve 7 to the shaft 5. Therefore, the workability of the shaft 5 can be improved while stabilizing the strength of the rotor 3.

[0100] (8) The rotor 3 according to the eighth embodiment is the rotor 3 of (7), wherein the shaft 5 has a hole forming portion 50A having an insertion hole 52 into which the connecting shaft 6 is inserted, and a solid portion 50B formed on the second side Da2 in the axial direction Da relative to the hole forming portion 50A, and the sleeve 7 and the shaft 5 are fitted together by shrink fitting at a position in the axial direction Da where the solid portion 50B overlaps.

[0101] This suppresses deformation of the shaft 5 and allows the sleeve 7 to be firmly fixed to the shaft 5. Furthermore, if the sleeve 7 is fitted by shrink fitting at a position overlapping with the hole-forming portion 50A, the tightening force from the sleeve 7 may deform the hole-forming portion 50A, potentially making it difficult to insert the connecting shaft 6 into the insertion hole 52 in the hole-forming portion 50A. In contrast, by fitting the sleeve 7 by shrink fitting at a position overlapping with the solid portion 50B, deformation of the insertion hole 52 is suppressed, and the ease of assembly of the rotor 3 can be maintained.

[0102] (9) The rotor 3 according to the ninth embodiment is any one of the rotors 3 from (1) to (8), and has a sealing portion 9 that seals the space between the outer circumferential surface of the shaft 5 and the inner circumferential surface of the sleeve 7.

[0103] This makes it possible to prevent corrosive gases compressed by the impeller 4 from reaching the shaft 5 when a corrosive gas is used as the working fluid in a rotating machine 1 equipped with such a rotor 3.

[0104] (10) The rotating machine 1 according to the tenth embodiment comprises a rotor 3 from any one of (1) to (9) and a casing 2 that covers the rotor 3 from the outer Dro in the radial direction Dr.

[0105] This makes it possible to provide a rotating machine 1 equipped with a rotor 3 that can firmly restrain the impeller 4 and the shaft 5 in the radial direction Dr and the circumferential direction Dc.

[0106] (11) A rotor assembly method according to the 11th embodiment is a rotor assembly method of any one of (1) to (9), comprising: step S11 of fixing the sleeve 7 to the shaft 5; step S12 of connecting the connecting shaft 6 to the shaft 5; step S13 of inserting the connecting shaft 6 into the insertion hole 46 of the impeller 4 from the axial direction Da, and bringing the impeller end face 471 and the sleeve end face 72 into contact to restrain each other's positions; and step S14 of fastening the nut 8 to the threaded portion 63 of the connecting shaft 6.

[0107] This improves the ease of assembly of the rotor 3 while firmly restraining the impeller 4 and shaft 5 in the radial direction Dr and the circumferential direction Dc. [Explanation of Symbols]

[0108] 1… Geared compressor (rotating machine) 2…Casing 3…Rotor 4… Impeller 4A...First stage impeller 4B...Second stage impeller 5…Shaft 5a...end 5s…Shaft end face 6...Connection shaft 7... Sleeves 7f…Inner peripheral surface 8... Nut 9... Seal part 11... Speed-increasing transmission unit 12…Radial bearings 15... Pinion gear 16...Large diameter gear 17…Thrust bearings 21...Shaft insertion hole 22... Intake nozzle 22a... Inlet 23… Exhaust passage 40... Impeller body 41…Disk 41a...First disk surface 41b...Second disk surface 42... Blade 44... Impeller flow path 44i…Inlet 44o... Outlet 46…Through hole 461...First hole 462...Second hole 47...Protruding part 471... Impeller end face 48...Second mating section 481...Second protrusion 482...Second recess 483…Second side 484…Second separation surface 485...Second connection surface 50A…hole forming part 50B... Middle School 52… Insertion hole 521...Female thread section 61... Shaft body 62... Insertion shaft 63...Screw part 64…Flange section 72... Sleeve end face 73...First mating section 731...First protrusion 732...First recess 733...front page 734...First separation surface 735...First connection surface 91...Sealing material 621...Male screw part Da... Axis Da1…first side Da2…Second side Dc…Circumferential direction Dr…Radial direction Dri…inside Dro... outside O…Axis line S10...Rotor assembly method S11... The process of securing the sleeve. S12... The process in which the connecting shafts are connected. S13... The process of setting the impeller. S14... The process of fastening the nut.

Claims

1. A shaft extending in the axial direction in which the axis extends, with the axis as the center, A connecting shaft is connected to the first end of the shaft in the axial direction, and has a threaded portion formed at its tip. An impeller having an impeller body formed in the shape of a disc with respect to the aforementioned axis, and an insertion hole in the center of the impeller body that penetrates in the axial direction and through which the connecting shaft is inserted, A cylindrical sleeve is fixed to the shaft so as to cover the shaft, positioned on the second side in the axial direction opposite to the first side of the impeller, and on the radially outer side with respect to the shaft as the axis, The impeller is provided with a nut positioned on the first axial side and fastened to the threaded portion, thereby sandwiching and fixing the impeller together with the sleeve in the axial direction, A rotor in which the sleeve end face facing the first side in the axial direction of the sleeve and the impeller end face facing the second side in the axial direction of the impeller are in contact and their positions in the circumferential and radial directions around the axis are constrained to each other.

2. The sleeve has a first fitting portion formed on the sleeve end face, in which a plurality of first protrusions and first recesses are arranged in the circumferential direction, with first protrusions and first recesses projecting in the axial direction from a first surface facing the first side in the axial direction. The impeller has a second fitting portion formed on the end face of the impeller, in which a second convex portion protrudes in the axial direction from a second surface facing the second side in the axial direction and a second recessed portion is arranged in a plurality in the circumferential direction. The first protrusion fits into the second recess while mutually restricting each other's movement in the circumferential direction. The rotor according to claim 1, wherein the first recess is fitted with the second protrusion in such a manner that their circumferential movement is mutually restricted.

3. The first fitting portion is, Multiple first surfaces facing in the axial direction, When viewed from the axial direction, a plurality of first spaced surfaces are arranged alternately with respect to the first surface and spaced apart in the circumferential direction, and are formed at positions offset in the axial direction from the first surface, The first surface and the first separating surface are arranged in the circumferential direction and have a plurality of first connecting surfaces that connect the first surface and the first separating surface, The second fitting portion is, When viewed from the axial direction, a plurality of second surfaces are positioned to overlap with the first surface and are oriented in the axial direction, 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 relative to the second 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 surface and the second separating surface, The rotor according to claim 2, wherein the plurality of first connecting surfaces are in contact with at least a portion of the plurality of second connecting surfaces.

4. The first surface, when viewed from the radial direction, is located on the first side in the axial direction with respect to the first spaced surface. The rotor according to claim 3, wherein the plurality of first connecting surfaces, when viewed from the radial direction, spread out in the circumferential direction away from the first surface as you move from the first side in the axial direction toward the second side.

5. The impeller has a protruding portion that extends cylindrically from the impeller body to the second side in the axial direction, The rotor according to claim 2 or 3, wherein the second fitting portion is formed on the protruding portion.

6. The rotor according to claim 5, wherein the protruding portion is formed at a distance from the connecting shaft and the shaft radially outward.

7. The rotor according to claim 1 or 2, wherein the sleeve and the shaft are fitted together by shrink fitting.

8. The aforementioned shaft is A hole forming section having an insertion hole into which the connecting shaft is inserted, It has a solid portion formed on the second side in the axial direction relative to the hole-forming portion, The rotor according to claim 7, wherein the sleeve and the shaft are fitted together by shrink-fitting at a position that overlaps with the solid portion in the axial direction.

9. The rotor according to claim 1 or 2, having a sealing portion that seals the space between the outer circumferential surface of the shaft and the inner circumferential surface of the sleeve.

10. A rotor according to claim 1 or 2, A casing that covers the rotor from the radially outer side, A rotating machine equipped with a rotating mechanism.

11. A method for assembling a rotor according to claim 1 or 2, The process of fixing the sleeve to the shaft, The process of connecting the connecting shaft to the shaft, The process involves inserting the connecting shaft into the insertion hole of the impeller from the axial direction, and bringing the impeller end face and the sleeve end face into contact to restrain each other's positions, The steps include fastening the nut to the threaded portion of the connecting shaft, A method for assembling a rotor, including [the part mentioned].

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