Rotor, rotary machine, rotor assembly method, and rotor disassembly method

Abstract

A rotor according to the present invention comprises: a shaft that has a shaft body and a protruding part, the shaft body extending in the axial direction and having an axial end part on a first side in the axial direction, and the protruding part extending from the axial end part to the first side; an adapter flange that is fixed to the axial end part and extends in the axial direction; and a nut that fixes the adapter flange. The shaft has a shaft end surface that faces the first side at the axial end part, the adapter flange has a first flange end surface that faces the first side, a second flange end surface that faces a second side, a through hole that passes through the first flange end surface and the second flange end surface in the axial direction, and a counterbore part that is recessed from the first flange end surface toward the second side to widen the diameter of the through hole and accommodates the tip of the protruding part, the protruding part has a first screw shaft, and the nut is fastened to the first screw shaft. When in contact, the shaft end surface and the second flange end surface restrain each other in the circumferential and radial directions.

Description

Rotor, rotating machine, rotor assembly method, and rotor disassembly method

[0001] This application claims priority to Japanese Patent Application No. 2024-087853, filed May 30, 2024, the contents of which are incorporated herein by reference.

[0002] Rotary machines are known that are used in industrial compressors, turbo refrigerators, small gas turbines, etc. When assembling such rotary machines into an operable state, it is necessary to mechanically couple the rotor of the rotary machine and the rotor of the driver.

[0003] A configuration for mechanically coupling a rotor of a rotary machine and a rotor of a driving machine is described, for example, in Patent Document 1. A coupling flange is attached to the end of a shaft, which is part of the rotor, and the rotor of the driving machine can be mechanically coupled via the coupling flange.

[0004] US Patent Application Publication No. 2020 / 0325906

[0005] However, a configuration such as the coupling flange described in Patent Document 1 is disposed so as to protrude outward in the axial direction from the bearing device that supports the rotor. If the mass of the portion protruding from the bearing device, i.e., the shaft end, becomes large, it is disadvantageous in terms of rotor dynamics. Therefore, a structure that can further reduce the weight of such a shaft end is desired.

[0006] The present disclosure provides a rotor, a rotary machine, a rotor assembly method, and a rotor disassembly method that can reduce the weight of the shaft end.

[0007] A rotor according to the present disclosure includes a shaft having a shaft body extending in an axial direction around an axis line and having an axial end portion on a first side in the axial direction, and a protrusion extending from the axial end portion toward the first side in the axial direction coaxially with the axial end portion, an adapter flange fixed to the axial end portion and extending in the axial direction around the axis line, and a nut that sandwiches and fixes the adapter flange together with the shaft in the axial direction, wherein the shaft has a shaft end face at the axial end portion facing the first side in the axial direction, and the adapter flange has a first flange end face facing the first side in the axial direction and a second flange end face facing the second side in the axial direction that is opposite to the first flange end face. a second flange end face that faces the shaft end face in the axial direction; a through hole that penetrates the first flange end face and the second flange end face in the axial direction and into which the protrusion is inserted; and a countersunk portion that is recessed from the first flange end face toward a second side in the axial direction so as to expand the through hole radially outward relative to the axis, and in which the tip of the protrusion is disposed, the protrusion having a first screw shaft with a thread formed on its outer peripheral surface, the nut being disposed inside the countersunk portion and fastened to the first screw shaft from the first side in the axial direction, the shaft end face and the second flange end face being in contact and having their positions in the circumferential direction around the axis and the radial direction constrained to each other.

[0008] A rotating device according to the present disclosure includes the rotor described above and a casing that covers the rotor from the outside in the radial direction.

[0009] The rotor assembly method according to the present disclosure is the rotor assembly method described above, and includes the steps of restricting circumferential rotation of the shaft relative to the axis of the shaft, inserting the protrusion into the through hole, and connecting the adapter flange and the shaft, and tightening the nut onto the first screw shaft.

[0010] The rotor disassembly method according to the present disclosure is a rotor disassembly method as described above, and includes the steps of removing the nut from the first screw shaft while restricting circumferential rotation of the shaft relative to the axis of the shaft, and removing the adapter flange from the shaft and pulling out the protrusion from the through hole.

[0011] According to the rotor, rotary machine, rotor assembly method, and rotor disassembly method of the present disclosure, the weight of the shaft end can be reduced.

[0012] Fig. 1 is a configuration diagram showing a schematic configuration of a rotary machine in an embodiment of the present disclosure; Fig. 2 is an enlarged view of a main part of a rotor in an embodiment of the present disclosure; Fig. 3 is a perspective view showing a first connection part and a second connection part formed on a rotor in an embodiment of the present disclosure; Fig. 4 is a flowchart showing the steps of an assembly method of a rotor in an embodiment of the present disclosure; Fig. 5 is a flowchart showing the steps of a disassembly method of a rotor in an embodiment of the present disclosure;

[0013] 1 to 5 , embodiments for implementing a rotor 3, a rotary machine 1, a rotor assembly method S10, and a rotor disassembly method S20 according to the present disclosure will be described below. In this embodiment, a multi-stage centrifugal compressor will be described as an example of the rotary machine 1. However, the present disclosure is not limited to this embodiment.

[0014] <Configuration of Rotary Machine> As shown in Fig. 1 , the rotary machine 1 according to this embodiment includes a casing 2 and a rotor 3. The casing 2 is formed so as to cover the rotor 3. The casing 2 forms the outer shell of the multi-stage centrifugal compressor. The casing 2 has a cylindrical shape extending in the direction in which the axis O of the rotor 3 extends (hereinafter, this direction will be referred to as the axial direction Da). The casing 2 has an internal space that repeatedly decreases and increases in diameter.

[0015] <Configuration of Rotor> The rotor 3 extends in the axial direction Da and is rotatable about an axis O relative to the casing 2. The rotor 3 includes a shaft 7, a stud bolt 5, an adapter flange 4, and a bolt.

[0016] The shaft 7 extends in the axial direction Da. The shaft 7 extends around the axis O. The shaft 7 is supported by a pair of radial bearings 8A fixed to the casing 2 so as to be rotatable about the axis O relative to the casing 2. Both ends of the shaft 7 in the axial direction Da are disposed outside the casing 2. The shaft 7 is connected to the adapter flange 4 at a shaft end 72, which is the end on the right side in FIG. 1 . The shaft end 72 is one end of the shaft 7 in the axial direction Da and is a region of the shaft 7 that includes an end face (shaft end face 721) facing the axial direction Da. The shaft end 72 is a region of the shaft 7 that is disposed outside the casing 2 in the axial direction Da. In the following description, the direction in the axial direction Da from the end of the shaft 7 opposite the axial end 72 (the end on the left side in FIG. 1 ) toward the axial end 72 will be referred to as a first side Da1, and the direction in the axial direction Da from the axial end 72 toward the other end of the shaft 7 will be referred to as a second side Da2. Details of the structure around the axial end 72 of the shaft 7 will be described later.

[0017] As shown in Figure 1, the shaft 7 is supported by a pair of radial bearings 8A so as to be rotatable about an axis O. The pair of radial bearings 8A are arranged at a distance from each other in the axial direction Da. The movement of the shaft 7 in the axial direction Da is restricted by a pair of thrust bearings 8B. The pair of thrust bearings 8B are arranged on a second side Da2 in the axial direction Da relative to the pair of radial bearings 8A. In this embodiment, the thrust bearing 8B has a cover 21 that covers the other end of the shaft 7.

[0018] The shaft 7 is connected to a plurality of impellers 9. The impellers 9 are rotatable together with the shaft 7. The impellers 9 compress the process gas G taken into the casing 2 by centrifugal force. A plurality of impellers 9 are provided at intervals in the axial direction Da, and each is housed in the internal space of the casing 2. In this embodiment, a case where six impellers 9 are arranged is shown as an example, but the number of impellers 9 is not limited to six.

[0019] Figure 2 is an enlarged view of the shaft end portion 72 and the vicinity of the adapter flange 4 in an embodiment of the present disclosure. As shown in Figure 2, the shaft 7 includes a shaft body 71 and a protrusion 10 that extends coaxially with the shaft body 71 from the shaft body 71 toward the first side Da1 in the axial direction Da. In this embodiment, the protrusion 10 is part of the stud bolt 5. That is, the shaft 7 in this embodiment includes the shaft body 71 and the stud bolt 5.

[0020] The shaft body 71 refers to a region of the shaft 7 that includes the shaft end portion 72 and extends in the axial direction Da. The shaft body 71 extends in the axial direction Da around the axis O so as to penetrate the casing 2. The shaft end portion 72 is disposed on a first side Da1 in the axial direction Da of the shaft body 71. As shown in FIG. 3 , the shaft body 71 of this embodiment includes a shaft end surface 721, a first connecting portion 73, a screw hole 74, and an accommodating recess 75.

[0021] The shaft end surface 721 faces a first side Da1 in the axial direction Da at the shaft end portion 72. The shaft end surface 721 is a plane that extends perpendicular to the axis O. The shaft end surface 721 is disposed at the end-most portion of the shaft body 71 in the axial direction Da. Therefore, the shaft body 71 extends from the shaft end surface 721 to a second side Da2 in the axial direction Da.

[0022] The first connecting portion 73 is formed to be connectable to the adapter flange 4. The first connecting portion 73 is formed on the shaft end surface 721. The first connecting portion 73 includes a first convex portion 731 and a first concave portion 732. The first convex portion 731 protrudes from the shaft end surface 721 toward a first side Da1 in the axial direction Da. The first concave portion 732 is recessed from the shaft end surface 721 toward a second side Da2 in the axial direction Da. When viewed from the axial direction Da, the first convex portions 731 and the first concave portions 732 are alternately arranged in a circumferential direction Dc centered on the axis O. The first connecting portion 73 has a plurality of first convex portions 731 and a plurality of first concave portions 732 (eight of each in this embodiment). The plurality of first convex portions 731 and first concave portions 732 are arranged at equal intervals in the circumferential direction Dc. When viewed from the axial direction Da, the first connecting portion 73 forms an annular region centered on the axis O at a position offset to the outer side Dro in the radial direction Dr from the axis O. Note that Fig. 3 omits configuration other than the first connecting portion 73.

[0023] Specifically, the first connecting 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 convex portions 731 and a plurality of first concave portions 732.

[0024] The first surfaces 733 are arranged at equal intervals in the circumferential direction Dc. Each first surface 733 is a flat surface facing the first side Da1 in the axial direction Da. The first surface 733 is a top surface of the first convex portion 731 that is located closest to the first side Da1 in the axial direction Da.

[0025] The first spaced apart surfaces 734 are arranged apart in the circumferential direction Dc from the first surface 733 so as to be staggered with respect to the first surface 733 when viewed from the axial direction Da. The first spaced apart surfaces 734 are formed at positions shifted in the axial direction Da from the first surface 733. In this embodiment, the first spaced apart surfaces 734 are formed at positions shifted to the second side Da2 in the axial direction Da from the first surface 733. The first spaced apart surfaces 734 are flat surfaces facing the first side Da1 in the axial direction Da. The first spaced apart surfaces 734 are bottom surfaces of the first recessed portions 732 that are located closest to the second side Da2 in the axial direction Da.

[0026] The first connecting surface 735 is disposed between adjacent first surfaces 733 and first separating surfaces 734 in the circumferential direction Dc. A plurality of first connecting surfaces 735 are disposed at intervals in the circumferential direction Dc. Each first connecting surface 735 connects the first surface 733 and the first separating surface 734. The first connecting surface 735 in this embodiment is formed as a flat surface so that, when viewed from the axial direction Da, the connection line with the first surface 733 and the connection line with the first separating surface 734 are linear and extend radially in the radial direction Dr centered on the axis O. In other words, the first connecting surface 735 is an inclined surface that faces the axial direction Da and the circumferential direction Dc and extends straight in the radial direction Dr.

[0027] The first convex portion 731 is formed by the first surface 733 and two first connecting surfaces 735 arranged on both sides of the first surface 733 in the circumferential direction Dc. The first recessed portion 732 is formed by the first separating surface 734 and two first connecting surfaces 735 arranged on both sides of the first separating surface 734 in the circumferential direction Dc.

[0028] When viewed in the radial direction Dr, the first connecting surfaces 735 widen so as to be away from the first surface 733 in the circumferential direction Dc as they move 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 arranged on both sides of the first convex portion 731 in the circumferential direction Dc gradually widens from the first side Da1 to the second side Da2 in the axial direction Da as viewed in the radial direction Dr. Furthermore, the distance between the first connecting surfaces 735 arranged on both sides of the first recessed portion 732 in the circumferential direction Dc gradually narrows from the first side Da1 to the second side Da2 in the axial direction Da as viewed in the radial direction Dr.

[0029] In the first connecting 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 this order, thereby forming multiple first convex portions 731 and first concave portions 732 in a shape similar to a hearth coupling.

[0030] The threaded hole 74 is formed so that the shaft body 71 and the stud bolt 5 can be connected. The threaded hole 74 is recessed from the shaft end face 721 toward the second side Da2 in the axial direction Da. The threaded hole 74 is formed to extend from the shaft end face 721 toward the second side Da2 in the axial direction Da. The threaded hole 74 is recessed about the axis O. A female thread is formed on the inner circumferential surface of the threaded hole 74.

[0031] The accommodating recess 75 is formed to be able to accommodate the flange 56 of the stud bolt 5, which will be described later. The accommodating recess 75 is recessed from the shaft end face 721 toward the second side Da2 in the axial direction Da. The accommodating recess 75 has a recess bottom surface 76 that faces the first side Da1 in the axial direction Da. The recess bottom surface 76 is formed closer to the first side Da1 in the axial direction Da than the end of the second side Da2 of the screw hole 74. The recess bottom surface 76 is a flat surface that extends perpendicular to the axis O.

[0032] The stud bolt 5 is formed to be able to fix the shaft body 71 and the adapter flange 4. The stud bolt 5 extends in the axial direction Da. The stud bolt 5 extends about the axis O. In other words, the stud bolt 5 extends coaxially with the shaft body 71. The stud bolt 5 includes a first portion 51, a second portion 54, and a flange portion 56.

[0033] The first portion 51 is the protrusion 10 described above. The first portion 51 is formed to be insertable into a through-hole 45 of the adapter flange 4, which will be described later. The first portion 51 extends from the shaft end surface 721 to a first side Da1 in the axial direction Da when the stud bolt 5 and the shaft body 71 are connected. In other words, the first portion 51 is formed to protrude from the shaft end portion 72 toward the first side Da1 in the axial direction Da. The first portion 51 of this embodiment includes a first screw shaft 52 and an expanded diameter shaft portion 53.

[0034] The first screw shaft 52 is formed so that the nut 6 can be fastened thereto. The first screw shaft 52 is formed in a cylindrical shape centered on the axis O, and has a male thread formed on its outer circumferential surface. The first screw shaft 52 extends in the axial direction Da from the end of the first side Da1 of the first portion 51 toward the second side Da2. In this embodiment, the first screw shaft 52 is not formed on the entire first portion 51. In other words, the first portion 51 has a portion on its outer circumferential surface where the male thread is formed and a portion where the male thread is not formed, but this is not limited to this. The first portion 51 may have a male thread formed on the entire outer circumferential surface.

[0035] The expanded diameter shaft portion 53 is formed to be disposed inside the through hole 45 of the adapter flange 4. The expanded diameter shaft portion 53 is formed in a portion of the first portion 51 where no male threads are formed on the outer peripheral surface. The expanded diameter shaft portion 53 is formed to expand the diameter of the first portion 51 toward the outer side Dro in the radial direction Dr. This can also be said to mean that the expanded diameter shaft portion 53 is formed to expand the diameter of the first screw shaft 52 toward the outer side Dro in the radial direction Dr. Furthermore, in a configuration in which a male thread is formed along the entire outer peripheral surface of the first portion 51, the expanded diameter shaft portion 53 may be formed by expanding the diameter of a portion of the first portion 51 toward the outer side Dro in the radial direction Dr. The expanded diameter shaft portion 53 extends in the axial direction Da. In this embodiment, the expanded diameter shaft portion 53 is provided spaced apart from the first shaft portion and the flange portion 56 in the axial direction Da.

[0036] The flange 56 prevents the stud bolt 5 from being attached to the shaft body 71 at an angle with respect to the axial direction Da. The flange 56 is disposed between the first portion 51 and the second portion 54 with respect to the axial direction Da. That is, the flange 56 of this embodiment extends from the first portion 51 to the second side Da2 in the axial direction Da. The flange 56 is formed to extend outward in the radial direction Dr beyond the first portion 51 and the second portion 54. The flange 56 has a flange contact surface 57 on the second side Da2 in the axial direction Da. The flange contact surface 57 faces the second side Da2 in the axial direction Da. The flange contact surface 57 is a flat surface that extends perpendicular to the axis O. When the shaft body 71 and the stud bolt 5 are connected, the flange contact surface 57 and the recess bottom surface 76 abut against each other.

[0037] The second portion 54 is formed to be connectable to the shaft main body 71. The second portion 54 extends toward the second side Da2 relative to the first portion 51 in the axial direction Da. In this embodiment, the second portion 54 extends from the flange portion 56 toward the second side Da2 in the axial direction Da. The second portion 54 has a second screw shaft 55. The second screw shaft 55 is formed in a cylindrical shape centered on the axis O, and has a male thread formed on its outer circumferential surface. The second screw shaft 55 is formed to thread into the screw hole 74. The shaft main body 71 and the stud bolt 5 are connected by inserting the second screw shaft 55 into the screw hole 74. In this embodiment, the second screw shaft 55 is not formed on the entire second portion 54. In other words, the second portion 54 has portions on its outer circumferential surface where a male thread is formed and portions where a non-male thread is formed, but this is not limited to this. The second portion 54 may have a male thread formed over the entire outer circumferential surface. Furthermore, although the tip of the second portion 54 on the second side Da2 in the axial direction Da is sharp in this embodiment, the present invention is not limited to this.

[0038] The adapter flange 4 enables mechanical connection between the shaft 7 and the rotor (not shown) of the driving machine. The adapter flange 4 is connectable to the shaft 7 by being fixed to the shaft end portion 72. The adapter flange 4 extends in the axial direction Da. The adapter flange 4 extends about the axis O. The adapter flange 4 is made of a material having the same linear expansion coefficient as the shaft 7. The adapter flange 4 of this embodiment includes a first outer circumferential portion 43, an enlarged diameter portion 41, a through hole 45, a counterbore portion 46, and a second connecting portion 48.

[0039] The first outer circumferential portion 43 extends in the axial direction Da. The first outer circumferential portion 43 is connected to the expanded diameter portion 41 in the axial direction Da. The first outer circumferential portion 43 has a second flange end surface 44 on a second side Da2 in the axial direction Da. The second flange end surface 44 is formed to face the shaft end surface 721 in the axial direction Da. The second flange end surface 44 faces the second side Da2 in the axial direction Da. The second flange end surface 44 is a plane that extends perpendicular to the axis O. In this embodiment, the first outer circumferential portion 43 has the same diameter as the shaft main body 71 in the radial direction Dr, but this is not limited to this. It is preferable that the first outer circumferential portion 43 has a diameter equal to or smaller than that of the shaft main body 71 in the radial direction Dr.

[0040] The expanded diameter portion 41 is formed to be mechanically connectable to an end of a rotor of a driving machine (not shown). The expanded diameter portion 41 has a first flange end face 42 on a first side Da1 in the axial direction Da. That is, the first flange end face 42 and the second flange end face 44 face opposite each other in the axial direction Da. The second flange end face 44 faces one side in the axial direction Da. The second flange end face 44 is a plane extending perpendicular to the axis O. The expanded diameter portion 41 extends toward the outer side Dro in the radial direction Dr relative to the first outer peripheral portion 43. Furthermore, the end of the first portion 51 on the first side Da1 in the axial direction Da is located on a second side Da2 in the axial direction Da relative to the first flange end face 42. In other words, the first portion 51 does not protrude toward the second side Da2 beyond the first flange end face 42 in the axial direction Da.

[0041] The through hole 45 is formed so that the first portion 51 can be inserted therein. That is, the diameter of the through hole 45 is formed to be larger than the expanded diameter shaft portion 53. The through hole 45 penetrates the first flange end surface 42 and the second flange end surface 44 in the axial direction Da. When the first portion 51 is inserted therein, the through hole 45 does not come into contact with the first portion 51. However, this is not limited thereto, and for example, the expanded diameter shaft portion 53 and the through hole 45 may be formed so that they come into contact with each other.

[0042] Furthermore, when the first portion 51 is inserted into the through hole 45, the positional relationship between the through hole 45 and the expanded diameter shaft portion 53 is as follows: The expanded diameter shaft portion 53 is disposed inside the through hole 45. The expanded diameter shaft portion 53 is disposed spaced apart from the second flange end face 44 in the axial direction Da. That is, the expanded diameter shaft portion 53 is disposed spaced apart from the second flange end face 44 on the first side Da1 in the axial direction Da. In the axial direction Da, the ratio of the length of the expanded diameter shaft portion 53 (X in FIG. 2 ) to the length between the first flange end face 42 and the second flange end face 44 (A in FIG. 2 ) is preferably 0.5 or less. It is more preferable that this length ratio be 0.3 or less. However, the structure is not limited to such a length ratio.

[0043] The countersunk portion 46 is formed so that the washer 6A and the nut 6 can be disposed therein. That is, the diameter of the countersunk portion 46 is formed to be larger than the washer 6A and the nut 6. The countersunk portion 46 is also formed so that the diameter of the through hole 45 expands toward the outer side Dro in the radial direction Dr with respect to the axis O. The countersunk portion 46 is formed so as to be recessed from the first flange end surface 42 toward the second side Da2 in the axial direction Da. The end of the first portion 51 on the first side Da1 in the axial direction Da is disposed inside the countersunk portion 46.

[0044] The second connecting portion 48 is formed to be connectable to the shaft main body 71. The second connecting portion 48 is formed on the second flange end surface 44. The second connecting portion 48 is formed at a position overlapping the first connecting portion 73 when viewed from the axial direction Da. Specifically, the second connecting portion 48 is formed to fit with the first connecting portion 73. The second connecting portion 48 includes a second convex portion 481 and a second concave portion 482. The second convex portion 481 protrudes from the second flange end surface 44 toward the second side Da2 in the axial direction Da. The second concave portion 482 is recessed from the second flange end surface 44 toward the first side Da1 in the axial direction Da. When viewed from the axial direction Da, the second convex portions 481 and the second concave portions 482 are alternately arranged in the circumferential direction Dc centered on the axis O. The second connecting portion 48 has a plurality of second convex portions 481 and second concave portions 482 (eight of each in this embodiment). The second convex portions 481 and the second concave portions 482 are disposed at equal intervals in the circumferential direction Dc. When viewed from the axial direction Da, the second connection portion 48 forms an annular region centered on the axis O at a position offset from the axis O to the outer side Dro in the radial direction Dr.

[0045] Further, the second connecting 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, the plurality of second separating surfaces 484, and the plurality of second connecting surfaces 485 form a plurality of second convex portions 481 and a plurality of second concave portions 482.

[0046] The second surface 483 is a flat surface facing the second side Da2 in the axial direction Da. The second surface 483 is formed to have the same size as the first surface 733 when viewed from the axial direction Da. Furthermore, the second surface 483 is disposed at a position overlapping the first surface 733 when viewed from the axial direction Da. The second surface 483 is a bottom surface of the second recess 482 that is located closest to the first side Da1 in the axial direction Da.

[0047] The second spaced apart surfaces 484 are disposed apart 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 spaced apart surfaces 484 are formed at positions offset from the second surface 483 in the axial direction Da. In this embodiment, the second spaced apart surfaces 484 are formed at positions offset toward the second side Da2 in the axial direction Da with respect to the second surface 483. The second spaced apart surfaces 484 are flat surfaces facing the second side Da2 in the axial direction Da. When viewed from the axial direction Da, the second spaced apart surfaces 484 are formed smaller than the second surface 483. When viewed from the axial direction Da, the second spaced apart surfaces 484 are formed to have the same size as the first spaced apart surfaces 734. The second spaced apart surfaces 484 are top surfaces of the second convex portions 481 that are located closest to the second side Da2 in the axial direction Da. The second spaced apart surfaces 484 are disposed at positions overlapping with the first spaced apart surfaces 734 when viewed from the axial direction Da.

[0048] The second connecting surface 485 is disposed between the adjacent second surface 483 and second separating surface 484 in the circumferential direction Dc. A plurality of second connecting surfaces 485 are disposed at intervals in the circumferential direction Dc. Each second connecting surface 485 connects the second surface 483 and the second separating surface 484. In this embodiment, the second connecting surface 485 is formed as a flat surface so that, when viewed from the axial direction Da, the connection line with the second surface 483 and the connection line with the second separating surface 484 are linear and extend radially in the radial direction Dr from the axis O. In other words, the second connecting surface 485 is an inclined surface that faces the axial direction Da and the circumferential direction Dc and extends straight in the radial direction Dr. When viewed from the axial direction Da, the second connecting surface 485 is disposed at a position overlapping with the first connecting surface 735. When viewed from the axial direction Da, the second connecting surface 485 is formed to have the same size as the first connecting surface 735.

[0049] The second recess 482 is formed by the second surface 483 and two second connecting surfaces 485 arranged on both sides of the second surface 483 in the circumferential direction Dc. The second separating surface 484 and two second connecting surfaces 485 arranged on both sides of the second separating surface 484 in the circumferential direction Dc form the second convex portion 481. Therefore, in the second connecting portion 48, the arrangement order of the second convex portions 481 and the second recessed portions 482 in the circumferential direction Dc is reversed from the arrangement order of the first convex portions 731 and the first recessed portions 732 in the circumferential direction Dc of the first connecting portion 73.

[0050] When viewed in the radial direction Dr, the second connecting surfaces 485 widen so as to be away from the second surface 483 in the circumferential direction Dc as they move 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 arranged on both sides of the second convex portion 481 in the circumferential direction Dc gradually narrows from the first side Da1 to the second side Da2 in the axial direction Da as viewed in the radial direction Dr. Furthermore, the distance between the second connecting surfaces 485 arranged on both sides of the second recessed portion 482 in the circumferential direction Dc gradually widens from the first side Da1 to the second side Da2 in the axial direction Da as viewed in the radial direction Dr.

[0051] In the second connection portion 48, the second surface 483, the second connection surface 485, the second separation surface 484, the second connection surface 485, and the second surface 483 are repeatedly arranged in the circumferential direction Dc in this order, thereby forming multiple second recesses 482 and second protrusions 481 in a shape similar to a hearth coupling.

[0052] Furthermore, when the first connecting portion 73 and the second connecting portion 48 are fitted together, the first connecting surface 735 and the second connecting surface 485 are in contact with each other. 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 may face each other with a gap in between in the axial direction Da. It is sufficient that the multiple first connecting surfaces 735 are in contact with at least a portion of the multiple second connecting surfaces 485.

[0053] The shaft main body 71 and the adapter flange 4 are in contact with each other in the axial direction Da at the shaft end surface 721 and the second flange end surface 44. When the shaft end surface 721 and the second flange end surface 44 are in contact with each other, their positions in the circumferential direction Dc and the radial direction Dr are restricted. Specifically, the first convex portion 731 is formed to fit into the second concave portion 482 while restricting their movement in the circumferential direction Dc. The first concave portion 732 is formed to fit into the second convex portion 481 while restricting their movement in the circumferential direction Dc. By fitting the first connecting portion 73 and the second connecting portion 48 in this manner, the shaft end surface 721 and the second flange end surface 44 are in contact with each other while their positions in the circumferential direction Dc and the radial direction Dr are restricted.

[0054] The nut 6 is disposed inside the counterbore 46. The nut 6 is fastened to the first screw shaft 52 from a first side Da1 in the axial direction Da. When fastened to the first screw shaft 52, the nut 6 sandwiches and fixes the adapter flange 4 together with the shaft body 71 in the axial direction Da. The nut 6 is formed in a disk shape centered on the axis O. An internal thread that threadably engages with the first screw shaft 52 is formed on the inner peripheral surface of the nut 6. The length of the nut 6 in the axial direction Da is formed so that the end of the first screw shaft 52 on the first side Da1 in the axial direction Da of the first screw shaft 52 protrudes. When fastened to the first screw shaft 52, the nut 6 is fixed to the first screw shaft 52 while pressing the adapter flange 4 toward the shaft body 71 in the axial direction Da. Note that in this embodiment, a washer 6A is provided between the adapter flange 4 and the nut 6 in the axial direction Da, but the washer 6A may not be provided.

[0055] <Procedure of rotor assembly method> Next, a rotor assembly method S10 according to this embodiment will be described with reference to the flowchart shown in Fig. 4. The rotor assembly method S10 according to this embodiment includes a preparation step S11, a bolt attachment step S12, a flange attachment step S13, and a nut tightening step S14.

[0056] First, a preparation step S11 is performed. In this preparation step S11, the components that make up the rotor 3 described above are prepared. In this state, the impeller 9 is connected to the shaft 7, and the shaft 7 is supported by a bearing. In other words, this is a state in which only the assembly around the shaft end 72 is performed.

[0057] After the preparation step S11, the bolt installation step S12 is performed. In this bolt installation step S12, first, a measure is taken to restrict rotation of the shaft 7 in the circumferential direction Dc. This is performed using, for example, a jig. With the shaft 7 not rotating in the circumferential direction Dc, the second portion 54 is inserted into the threaded hole 74. The second portion 54 is inserted into the threaded hole 74 until the flange contact surface 57 and the accommodating recess 75 abut. This connects and fixes the shaft body 71 and the stud bolt 5. Note that if the shaft body 71 and the stud bolt 5 are integrated, i.e., if the shaft 7 includes the shaft body 71 and the protrusion 10, the bolt installation step S12 is omitted. However, the measure to restrict rotation of the shaft 7 in the circumferential direction Dc is performed before the next step is performed.

[0058] After the bolt attachment step S12, the flange attachment step S13 is performed. In the flange attachment step S13, the first portion 51 is inserted into the through hole 45. That is, in the flange attachment step S13, the adapter flange 4 is moved from the first side Da1 to the second side Da2 in the axial direction Da. In this state, the first portion 51 is inserted into the through hole 45 using the enlarged diameter shaft portion 53 as a guide, thereby aligning the axes of the shaft 7 and the adapter flange 4. The adapter flange 4 is moved toward the second side Da2 in the axial direction Da until the first connecting portion 73 and the second connecting portion 48 are connected, i.e., until the adapter flange 4 and the shaft main body 71 are connected. Note that the flange attachment step S13 is preferably performed in a state in which the shaft 7 is not rotating in the circumferential direction Dc, but this is not necessary. Note that using the enlarged diameter shaft portion 53 as a guide means that the adapter flange 4 is moved while the enlarged diameter shaft portion 53 abuts against the interior of the through hole 45. Furthermore, in the flange mounting process S13, there may be times when the enlarged diameter shaft portion 53 and the inside of the through hole 45 do not abut, or the adapter flange 4 may be mounted without the enlarged diameter shaft portion 53 and the inside of the through hole 45 abutting at all.

[0059] After the flange mounting step S13 is performed, the nut tightening step S14 is performed. In the nut tightening step S14, the nut 6 is tightened onto the first screw shaft 52 from the first side Da1 in the axial direction Da. A washer 6A is also provided so as to be sandwiched between the nut 6 and the adapter flange 4 in the axial direction Da. The adapter flange 4 is temporarily tightened to the shaft main body 71 by the washer 6A and the nut 6. Thereafter, the nut 6 is retightened to a predetermined arc angle. As a result, the adapter flange 4 is sandwiched and fixed between the shaft main body 71 and the nut 6. Note that the nut tightening step S14 is performed in a state in which the shaft 7 is not rotating in the circumferential direction Dc.

[0060] <Procedure of rotor disassembly method> Next, a rotor disassembly method S20 according to this embodiment will be described with reference to the flowchart shown in Fig. 5. The rotor disassembly method S20 according to this embodiment includes a preparation step S21, a nut removal step S22, a flange removal step S23, and a bolt removal step S24.

[0061] First, a preparation step S21 is performed in which the rotor 3 described above is prepared.

[0062] After the preparation step S21 is performed, the nut removal step S22 is performed. In this nut removal step S22, first, a procedure is performed to restrict rotation of the shaft 7 in the circumferential direction Dc. This is performed using, for example, a jig. With the shaft 7 not rotating in the circumferential direction Dc, the nut 6 is loosened and removed from the first screw shaft 52. The washer 6A is also removed from the first screw shaft 52 in the same manner.

[0063] After the nut removal step S22 is performed, the flange removal step S23 is performed. In the flange removal step S23, the adapter flange 4 is moved from the second side Da2 to the first side Da1 in the axial direction Da. Accordingly, the first portion 51 is pulled out of the through hole 45. At this time, the expanded diameter shaft portion 53 may be used as a guide. The flange removal step S23 is preferably performed in a state in which the shaft 7 is not rotating in the circumferential direction Dc, but this is not essential. Using the expanded diameter shaft portion 53 as a guide means that the adapter flange 4 is moved while the expanded diameter shaft portion 53 is in contact with the interior of the through hole 45. In the flange removal step S23, the expanded diameter shaft portion 53 may not be in contact with the interior of the through hole 45 at times, or the adapter flange 4 may be removed without any contact between the expanded diameter shaft portion 53 and the interior of the through hole 45.

[0064] After the flange removal step S23 is performed, the bolt removal step S24 is performed. In the bolt removal step S24, the second portion 54 is removed from the threaded hole 74. This removes the stud bolt 5 from the shaft main body 71. Note that the bolt removal step S24 is performed in a state where the shaft 7 is not rotating in the circumferential direction Dc. Furthermore, if the shaft main body 71 and the stud bolt 5 are integrated, that is, if the shaft 7 includes the shaft main body 71 and the protrusion 10, the bolt removal step S24 is omitted.

[0065] <Operation and Effect> According to the rotor 3 and rotating machine 1 described above, the first portion 51 fixed to the shaft body 71 is inserted into the through hole 45 to connect the shaft body 71 and the adapter flange 4. At this time, the nut 6 is fastened to the first screw shaft 52, so that the adapter flange 4 is sandwiched and fixed in the axial direction Da by the shaft body 71 and the nut 6. The shaft end face 721 and the second flange end face 44 are constrained in their positions in the circumferential direction Dc and the radial direction Dr while in contact with each other. As a result, the shaft body 71 and the adapter flange 4 are fixed in a state where they cannot move relative to each other in the axial direction Da, the circumferential direction Dc, and the radial direction Dr. In other words, simply by attaching the nut 6 to the first screw shaft 52, the adapter flange 4 can be easily attached to the shaft body 71 in a state where it cannot move relative to the shaft body 71. Therefore, the adapter flange 4 and the shaft body 71 can be firmly constrained in the radial direction Dr and the circumferential direction Dc without using a shrink fit, and assembly can be improved. In this way, there is no need for a structure for fixing the adapter flange 4 to the shaft body 71 by shrink fitting, so the size of the adapter flange 4 in the radial direction Dr can be reduced.

[0066] Furthermore, the counterbore 46 positions the end of the first portion 51 on the first side Da1 in the axial direction Da relative to the first flange end face 42 on the second side Da2 in the axial direction Da. In other words, the counterbore 46 positions the protruding portion 10 on the second side Da2 in the axial direction Da relative to the first flange end face 42. This prevents the adapter flange 4 from becoming longer in the axial direction Da, while eliminating a structure that protrudes toward the second side Da2 in the axial direction Da beyond the shaft end face 721. As a result, the length of the adapter flange 4 in the axial direction Da can be reduced. Therefore, the size of the adapter flange 4 in the axial direction Da and the radial direction Dr can be reduced, thereby reducing the weight of the adapter flange 4. This reduces the weight of the shaft end.

[0067] Furthermore, according to this embodiment, the counterbore 46 positions the protrusion 10 on the second side Da2 in the axial direction Da relative to the first flange end face 42. In other words, there is no structure that protrudes toward the first side Da1 in the axial direction Da beyond the first flange end face 42. Therefore, when the adapter flange 4 and the end of the rotor of the driver are spaced apart in the axial direction Da, flexible connecting parts can be easily attached from the radial direction Dr.

[0068] The adapter flange 4 also includes a first outer circumferential portion 43 and an expanded diameter portion 41. The first outer circumferential portion 43 has a diameter equal to or smaller than that of the shaft 7 in the radial direction Dr. The expanded diameter portion 41 allows the adapter flange 4 to be mechanically connected to the rotor of the driving machine, while the diameter of the first outer circumferential portion 43 can be reduced. Reducing the diameter of the adapter flange 4 allows the weight of the adapter flange 4 to be reduced. Therefore, the weight of the shaft end can be further reduced.

[0069] Furthermore, the first connecting portions 73 and the second connecting portions 48, which are arranged in plurality in the circumferential direction Dc, restrict movement of the shaft 7 and the adapter flange 4 relative to each other in the circumferential direction Dc. Furthermore, the first connecting portions 73 have first convex portions 731 and first concave portions 732, and the second connecting portions 48 have second convex portions 481 and second concave portions 482. Movement of the shaft 7 and the adapter flange 4 in the circumferential direction Dc and the radial direction Dr is restricted relative to each other simply by the first convex portions 731 and the second concave portions 482 fitting together and the first concave portions 732 and the second convex portions 481 fitting together. Therefore, the position of the adapter flange 4 relative to the shaft 7 in the radial direction Dr can be aligned before the positions are completely fixed with the nut 6.

[0070] Furthermore, the adapter flange 4 and the shaft 7 are made of materials with the same linear expansion coefficient. Therefore, even in an environment where the temperature changes, the adapter flange 4 and the shaft 7 expand or contract in a manner that tracks each other. More specifically, the first connecting portion 73 and the second connecting portion 48 can be made to expand or contract in the same manner. Therefore, the connection between the shaft 7 and the adapter flange 4 can be maintained regardless of the temperature of the environment.

[0071] Further, the first portion 51 is formed with an expanded diameter shaft portion 53. In the radial direction Dr, the gap between the expanded diameter shaft portion 53 and the interior of the through hole 45 is smaller than the gap between the first portion 51 in a region excluding the expanded diameter shaft portion 53 and the interior of the through hole 45. Therefore, when attaching the adapter flange 4, the adapter flange 4 is moved in the axial direction Da while the interior of the through hole 45 and the expanded diameter shaft portion 53 are in contact. As a result, it is possible to easily align the axes of the shaft 7 and the adapter flange 4.

[0072] Furthermore, the expanded diameter shaft portion 53 is disposed at a distance on the first side Da1 in the axial direction Da from the second flange end surface 44. The greater the distance between the expanded diameter shaft portion 53 and the second flange end surface 44 in the axial direction Da, the more limited the angle at which the adapter flange 4 can be tilted relative to the shaft 7. This allows for more precise axial alignment between the shaft 7 and the adapter flange 4.

[0073] The length of the expanded diameter shaft portion 53 in the axial direction Da is set as follows. In the axial direction Da, the ratio of the length of the expanded diameter shaft portion 53 (X in FIG. 2 ) to the length between the first flange end surface 42 and the second flange end surface 44 (A in FIG. 2 ) is preferably 0.5 or less. It is more preferable that this length ratio be 0.3 or less. If the expanded diameter shaft portion 53 is formed long in the axial direction Da, the portion where the gap between the first portion 51 and the inside of the through hole 45 is narrowed becomes long. With such a structure, for example, there is a risk of scratches occurring due to seizure between the first portion 51 and the inside of the through hole 45. Therefore, it is preferable that the length of the expanded diameter shaft portion 53 in the axial direction Da be limited as described above. This reduces the possibility of seizure between the first portion 51 and the inside of the through hole 45 while maintaining the accuracy of axial alignment.

[0074] The shaft 7 of this embodiment also includes a shaft body 71 and a stud bolt 5. That is, the stud bolt 5 is removable from the shaft body 71. This makes it possible to replace or repair only the stud bolt 5. This improves the maintainability of the shaft 7. Furthermore, the shaft body 71 can be formed or repaired without having the protrusion 10 on the shaft body 71. This increases the degree of freedom in designing the formation of the shaft 7 and improves the maintainability of the shaft 7.

[0075] Furthermore, a flange 56 is formed on the stud bolt 5, and an accommodating recess 75 is formed on the shaft body 71. The flange contact surface 57 of the flange 56 abuts against the recess bottom surface 76 of the accommodating recess 75, connecting the stud bolt 5 to the shaft body 71. Because the flange contact surface 57 and the recess bottom surface 76 are formed perpendicular to the axial direction Da, the stud bolt 5 can be connected in parallel to the shaft body 71. This allows precise axial alignment between the stud bolt 5 and the shaft body 71.

[0076] According to the rotor assembly method S10 of this embodiment, the first portion 51 is inserted into the through hole 45, and the adapter flange 4 is attached to the shaft 7. At this time, the enlarged diameter shaft portion 53 is used as a guide, so the adapter flange 4 can be attached while aligning the axes of the shaft 7 and the adapter flange 4. This makes it easier to connect the first connecting portion 73 and the second connecting portion 48. Furthermore, using the enlarged diameter shaft portion 53 as a guide reduces the load applied to the first portion 51 by the adapter flange 4. This improves the durability of the first portion 51, i.e., the stud bolt 5.

[0077] According to the rotor disassembly method S20 of this embodiment, the first portion 51 is pulled out of the through hole 45, and the adapter flange 4 is removed from the shaft 7. At this time, the enlarged diameter shaft portion 53 is used as a guide, thereby reducing the load applied to the first portion 51 by the adapter flange 4. This improves the durability of the first portion 51, i.e., the stud bolt 5.

[0078] <Other Embodiments> Although the embodiments of the present disclosure have been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and design changes and the like are also included within the scope that does not deviate from the gist of the present disclosure.

[0079] For example, the first connecting portion 73 and the second connecting portion 48 may be separate from the shaft main body 71 and the adapter flange 4. The shaft main body 71 and the first connecting portion 73 may be manufactured separately from the adapter flange 4 and the second connecting portion 48, and may be configured by being fixed to each other.

[0080] Furthermore, the multiple first connecting surfaces 735 and the multiple second connecting surfaces 485 are not limited to being flat surfaces such that the connecting lines to other surfaces are linear. That is, the first convex portion 731 and the first concave portion 732 and the second convex portion 481 and the second concave portion 482 are not limited to being formed in a shape similar to that of a Hirth 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 connecting lines to other surfaces are curved. That is, the first convex portion 731 and the first concave portion 732 and the second convex portion 481 and the second concave portion 482 may be formed in a shape similar to that of a curvic coupling.

[0081] Furthermore, the enlarged diameter shaft portion 53 according to the embodiment may not be provided.

[0082] <Additional Notes> The rotor 3, the rotary machine 1, the rotor assembling method S10, and the rotor disassembling method S20 described in each embodiment can be understood, for example, as follows.

[0083] (1) A rotor 3 according to a first aspect includes a shaft 7 having a shaft main body 71 extending in an axial direction Da along which an axis O extends and having a shaft end portion 72 on a first side Da1 in the axial direction Da, and a protrusion 10 extending from the shaft end portion 72 toward the first side Da1 in the axial direction Da coaxially with the shaft end portion 72, an adapter flange 4 fixed to the shaft end portion 72 and extending in the axial direction Da around the axis O, and a nut 6 for clamping and fixing the adapter flange 4 together with the shaft 7 in the axial direction Da, and the shaft 7 has a shaft end surface 721 at the shaft end surface 72 facing the first side Da1 in the axial direction Da, and the adapter flange 4 has a first flange end surface 42 facing the first side Da1 in the axial direction Da and a second flange end surface 43 facing the second side Da1 in the axial direction Da that is opposite to the first flange end surface 42. 2 and facing the shaft end face 721 in the axial direction Da; a through hole 45 penetrating the first flange end face 42 and the second flange end face 44 in the axial direction Da and into which the protrusion 10 is inserted; and a countersunk portion 46 recessed from the first flange end face 42 toward a second side Da2 in the axial direction Da so as to expand the diameter of the through hole 45 to the outer side Dro in the radial direction Dr based on the axis O, and into which the tip of the protrusion 10 is disposed. The protrusion 10 has a first screw shaft 52 having a thread formed on its outer peripheral surface. The nut 6 is disposed inside the countersunk portion 46 and is fastened to the first screw shaft 52 from the first side Da1 in the axial direction Da. The shaft end face 721 and the second flange end face 44 are in contact with each other and are constrained in their positions in the circumferential direction Dc and the radial direction Dr about the axis O.

[0084] According to the above configuration, the protrusion 10 is inserted into the through hole 45, connecting the shaft body 71 and the adapter flange 4. By fastening the nut 6 to the first screw shaft 52, the adapter flange 4 is sandwiched and fixed in the axial direction Da by the shaft body 71 and the nut 6. Therefore, the adapter flange 4 can be fixed to the shaft 7 and the nut 6 in a state where it cannot move in the axial direction Da, the radial direction Dr, and the circumferential direction Dc. Furthermore, the counterbore 46 positions the end of the first portion 51 on the first side Da1 in the axial direction Da on the second side Da2 in the axial direction Da relative to the first flange end face 42. This prevents the adapter flange 4 from protruding further toward the second side Da2 in the axial direction Da than the shaft end face 721, while preventing the adapter flange 4 from becoming longer in the axial direction Da. As a result, the length of the adapter flange 4 in the axial direction Da can be reduced. Therefore, the size of the adapter flange 4 in the axial direction Da and the radial direction Dr can be reduced, thereby reducing the weight of the adapter flange 4. This allows the weight of the shaft end to be reduced.

[0085] (2) A rotor 3 according to a second aspect is the rotor 3 of (1), wherein the shaft 7 has a first connecting portion 73 in which a first convex portion 731 protruding from the shaft end face 721 in the axial direction Da and a first recessed portion 732 are arranged in a plurality of positions in the circumferential direction Dc, the adapter flange 4 has a second connecting portion 48 in which a second convex portion 481 protruding from the second flange end face 44 in the axial direction Da and a second recessed portion 482 are arranged in a plurality of positions in the circumferential direction Dc, the first convex portion 731 fits into the second recessed portion 482 in a state in which their movements in the circumferential direction Dc are mutually restricted, and the first recessed portion 732 fits into the second convex portion 481 in a state in which their movements in the circumferential direction Dc are mutually restricted.

[0086] According to the above configuration, the first connecting portion 73 has a first convex portion 731 and a first concave portion 732, and the second connecting portion 48 has a second convex portion 481 and a second concave portion 482. The first convex portion 731 and the second concave portion 482 are fitted together, and the first concave portion 732 and the second convex portion 481 are fitted together, and this alone restricts the movement of the shaft 7 and the adapter flange 4 in the circumferential direction Dc and the radial direction Dr. Therefore, the position of the adapter flange 4 in the radial direction Dr relative to the shaft 7 can be aligned before the positions are completely fixed with the nut 6.

[0087] (3) The rotor 3 according to the third aspect is the rotor 3 of (1) or (2), in which the protrusion 10 is positioned on the second side Da2 in the axial direction Da relative to the first flange end face 42.

[0088] According to the above configuration, it is possible to prevent the length of the adapter flange 4 in the axial direction Da from increasing, while eliminating a structure that protrudes toward the second side Da2 beyond the shaft end surface 721 in the axial direction Da. By reducing the length of the adapter flange 4 in the axial direction Da, it is possible to reduce the weight of the adapter flange 4. Therefore, it is possible to reduce the weight of the shaft end.

[0089] (4) A rotor 3 according to a fourth aspect is a rotor 3 according to any one of (1) to (3), wherein the adapter flange 4 has a first outer circumferential portion 43 on which the second flange end face 44 is formed and which extends in the axial direction Da, and an expanded diameter portion 41 on which the first flange end face 42 is formed and which expands toward the outer side Dro in the radial direction Dr relative to the first outer circumferential portion 43, and the first outer circumferential portion 43 has a diameter equal to or smaller than that of the shaft 7 in the radial direction Dr.

[0090] According to the above configuration, the diameter of the first outer peripheral portion 43 can be reduced while the expanded diameter portion 41 allows the adapter flange 4 to be mechanically connected to the rotor of the driving machine. By reducing the diameter of the adapter flange 4, the weight of the adapter flange 4 can be reduced. Therefore, the weight of the shaft end can be further reduced.

[0091] (5) A rotor 3 according to a fifth aspect is the rotor 3 according to any one of (1) to (4), in which the adapter flange 4 and the shaft 7 are made of materials having the same linear expansion coefficient.

[0092] With the above configuration, even in an environment where the temperature changes, the adapter flange 4 and the shaft 7 expand or contract in a manner that follows each other, so that the connection between the shaft 7 and the adapter flange 4 can be maintained regardless of the temperature of the environment.

[0093] (6) The rotor 3 according to the sixth aspect is the rotor 3 of any one of (1) to (5), wherein the protrusion 10 is arranged inside the through hole 45 in the axial direction Da and has an expanded diameter shaft portion 53 in which the first screw shaft 52 is expanded in the radial direction Dr.

[0094] According to the above configuration, the gap between the enlarged diameter shaft portion 53 and the interior of the through hole 45 in the radial direction Dr is smaller than the gap between the protrusion 10 in a region excluding the enlarged diameter shaft portion 53 and the interior of the through hole 45. When attaching the adapter flange 4, the adapter flange 4 is moved in the axial direction Da while the enlarged diameter shaft portion 53 abuts against the interior of the through hole 45. As a result, it is possible to easily align the axes of the shaft 7 and the adapter flange 4.

[0095] (7) The rotor 3 according to the seventh aspect is the rotor 3 of (6), in which the enlarged diameter shaft portion 53 is positioned at a distance from the second flange end face 44 on the first side Da1 in the axial direction Da.

[0096] According to the above configuration, the greater the separation between the enlarged diameter shaft portion 53 and the second flange end surface 44 in the axial direction Da, the more restricted the angle at which the adapter flange 4 can be tilted relative to the shaft 7. This allows for more precise axial alignment between the shaft 7 and the adapter flange 4.

[0097] (8) The rotor 3 according to the eighth aspect is the rotor 3 of (6) or (7), in which the ratio of the length of the expanded diameter shaft portion 53 in the axial direction Da to the length of the first flange end face 42 and the second flange end face 44 in the axial direction Da is 0.5 or less.

[0098] According to the above configuration, the length of the expanded diameter shaft portion 53 in the axial direction Da is limited. If the expanded diameter shaft portion 53 is formed long in the axial direction Da, the portion where the gap between the protrusion 10 and the inside of the through hole 45 becomes small becomes long, which may cause scratches due to seizure between the protrusion 10 and the inside of the through hole 45. Therefore, it is preferable that the length of the expanded diameter shaft portion 53 in the axial direction Da is limited as described above. This makes it possible to reduce the possibility of seizure between the first portion 51 and the inside of the through hole 45 while maintaining the accuracy of axial alignment.

[0099] (9) A rotor 3 according to a ninth aspect is the rotor 3 of any one of (1) to (8), wherein the shaft 7 further comprises a stud bolt 5 having a threaded hole 74 recessed from the shaft end face 721 toward the second side Da2 in the axial direction Da around the axis O, a first portion 51 extending in the axial direction Da around the axis O and inserted into the through hole 45 and having the first screw shaft 52, and a second portion 54 extending toward the second side Da2 in the axial direction Da relative to the first portion 51 in the axial direction Da and having a second screw shaft 55 threaded into the threaded hole 74, wherein the second screw shaft 55 is inserted into the threaded hole 74 to connect the shaft body 71 and the stud bolt 5, and the protrusion 10 is the first portion 51.

[0100] According to the above configuration, the stud bolts 5 are removable from the shaft body 71. This makes it possible to replace or repair only the stud bolts 5. This improves the maintainability of the shaft 7. Furthermore, the shaft body 71 can be formed or repaired without the protrusion 10 on the shaft body 71. This increases the degree of freedom in designing the formation of the shaft 7 and improves the maintainability of the shaft 7.

[0101] (10) A rotor 3 according to a tenth aspect is the rotor 3 of (9), wherein the stud bolt 5 has a flange 56 that is wider in the radial direction Dr than the first portion 51 and the second portion 54, between the first portion 51 and the second portion 54 in the axial direction Da, the shaft body 71 has an accommodating recess 75 that is recessed from the shaft end face 721 toward the second side Da2 in the axial direction Da and can accommodate the flange 56, the flange 56 has a flange contact surface 57 facing the second side Da2 in the axial direction Da, and the accommodating recess 75 has a recess bottom surface 76 facing the first side Da1 in the axial direction Da, and the stud bolt 5 is connected to the shaft body 71 with the flange contact surface 57 abutting the recess bottom surface 76.

[0102] According to the above configuration, the flange contact surface 57 of the flange 56 abuts against the recess bottom surface 76 of the accommodating recess 75, connecting the stud bolt 5 to the shaft body 71. Because the flange contact surface 57 and the recess bottom surface 76 are formed perpendicular to the axial direction Da, the stud bolt 5 can be connected in parallel to the shaft body 71. This allows for precise axial alignment between the stud bolt 5 and the shaft body 71.

[0103] (11) A rotary machine 1 according to an eleventh aspect includes a rotor 3 according to any one of (1) to (10) and a casing 2 that covers the rotor 3 from the outside Dro in the radial direction Dr.

[0104] (12) A rotor assembly method S10 according to a twelfth aspect is a rotor assembly method S10 according to any one of (1) to (10), and includes a step of restricting rotation of the shaft 7 in the circumferential direction Dc based on the axis O of the shaft 7 relative to the shaft 7, inserting the protrusion 10 into the through hole 45, and connecting the adapter flange 4 and the shaft 7, and a step of fastening the nut 6 to the first screw shaft 52.

[0105] According to the above configuration, the protrusion 10 is inserted into the through hole 45, and the adapter flange 4 is attached to the shaft 7. At this time, the enlarged diameter shaft portion 53 is used as a guide, so the adapter flange 4 can be attached while aligning the axes of the shaft 7 and the adapter flange 4. This makes it easier to connect the first connecting portion 73 and the second connecting portion 48. Furthermore, using the enlarged diameter shaft portion 53 as a guide reduces the load applied to the protrusion 10 by the adapter flange 4. This improves the durability of the protrusion 10.

[0106] (13) A rotor disassembly method S20 according to a thirteenth aspect is a rotor disassembly method S20 according to any one of (1) to (10), and includes the steps of: removing the nut 6 from the first screw shaft 52 while restricting rotation of the shaft 7 in the circumferential direction Dc based on the axis O of the shaft 7; and removing the adapter flange 4 from the shaft 7 and pulling out the protrusion 10 from the through hole 45.

[0107] According to the above configuration, the protrusion 10 is pulled out of the through-hole 45, and the adapter flange 4 is removed from the shaft 7. At this time, the expanded diameter shaft portion 53 is used as a guide, thereby reducing the load applied to the protrusion 10 by the adapter flange 4. This improves the durability of the protrusion 10.

[0108] According to the rotor, rotary machine, rotor assembly method, and rotor disassembly method of the present disclosure, the weight of the shaft end can be reduced.

[0109] REFERENCE SIGNS LIST 1 Rotating machine 2 Casing 3 Rotor 4 Adapter flange 5 Stud bolt 6 Nut 6A Washer 7 Shaft 8 Bearing device 8A Radial bearing 8B Thrust bearing 9 Impeller 10 Protrusion 21 Cover 41 Enlarged diameter portion 42 First flange end face 43 First outer peripheral portion 44 Second flange end face 45 Through hole 46 Counterbore portion 48 Second connecting portion 481 Second convex portion 482 Second concave portion 483 Second surface 484 Second separating surface 485 Second connecting surface 51 First portion 52 First screw shaft 53 Enlarged diameter shaft portion 54 Second portion 55 Second screw shaft 56 Flange portion 57 Flange portion contact surface 71 Shaft body 72 Shaft end portion 721 Shaft end face 73 First connecting portion 731 First convex portion 732 First concave portion 733 First surface 734 First separation surface 735 First connection surface 74 Screw hole 75 Accommodation concave portion 76 Concave bottom surface G Process gas O Axis line Da Axial direction Da1 First side Da2 Second side Dr Radial direction Dri Inner side Dro Outer side Dc Circumferential direction S10 Rotor assembly method S11 Preparation step S12 Bolt attachment step S13 Flange attachment step S14 Nut tightening step S20 Rotor disassembly method S21 Preparation step S22 Nut removal step S23 Flange removal step S24 Bolt removal step

Claims

1. A shaft comprising: a shaft body extending in an axial direction around an axis line and having an axial end on a first side in the axial direction; and a protrusion extending from the axial end towards the first side in the axial direction coaxially with the axial end; an adapter flange fixed to the axial end and extending in the axial direction around the axis line; and a nut that sandwiches and fixes the adapter flange together with the shaft in the axial direction, wherein the shaft has a shaft end face at the axial end that faces the first side in the axial direction, and the adapter flange has: a first flange end face that faces the first side in the axial direction; and a second flange end face that faces a second side in the axial direction that is opposite to the first flange end face and faces opposite the shaft end face in the axial direction; and a through hole that penetrates the first flange end face and the second flange end face in the axial direction, and into which the protrusion is inserted. a countersunk portion recessed from the first flange end face toward the second axial side so as to expand the through hole radially outward relative to the axis, and in which the tip of the protrusion is disposed; the protrusion having a first screw shaft having a thread formed on its outer peripheral surface; the nut disposed inside the countersunk portion and fastened to the first screw shaft from the first axial side; and the shaft end face and the second flange end face being in contact with each other and constrained in their circumferential and radial positions around the axis.

2. The rotor according to claim 1, wherein the shaft has a first connecting portion in which a first convex portion protruding in the axial direction from the shaft end face and a first recessed portion recessed therein are arranged in a plurality in the circumferential direction, the adapter flange has a second connecting portion in which a second convex portion protruding in the axial direction from the second flange end face and a second recessed portion recessed therein are arranged in a plurality in the circumferential direction, the first convex portion fits into the second recess in a state in which the two portions are mutually restricted from moving in the circumferential direction, and the first recessed portion fits into the second convex portion in a state in which the two portions are mutually restricted from moving in the circumferential direction.

3. The rotor according to claim 1, wherein the protrusion is disposed on the second axial side of the first flange end face.

4. A rotor as described in claim 1, wherein the adapter flange has a first outer periphery on which the second flange end face is formed and which extends in the axial direction, and an expanded diameter portion on which the first flange end face is formed and which expands radially outward relative to the first outer periphery, and the first outer periphery has a diameter in the radial direction that is equal to or smaller than that of the shaft.

5. The rotor of claim 1, wherein said adapter flange and said shaft are constructed from materials having the same coefficient of linear expansion.

6. A rotor according to claim 1, wherein the protrusion is disposed inside the through hole in the axial direction and has an expanded diameter shaft portion in which the first screw shaft is expanded in the radial direction.

7. A rotor according to claim 6, wherein the enlarged diameter shaft portion is disposed on the first side in the axial direction and spaced apart from the second flange end face.

8. A rotor according to claim 6, wherein the ratio of the length of said expanded diameter shaft portion in the axial direction to the length of said first flange end face and said second flange end face in the axial direction is 0.5 or less.

9. The rotor according to claim 1, wherein the shaft further comprises: a threaded hole recessed from the shaft end face toward a second side in the axial direction around the axis; and a stud bolt having: a first portion extending in the axial direction around the axis and inserted into the through hole, the first threaded shaft being disposed therein; and a second portion extending to the second side in the axial direction relative to the first portion and having a second threaded shaft threadably engaging with the threaded hole; wherein the second threaded shaft is inserted into the threaded hole to connect the shaft body and the stud bolt; and the protruding portion is the first portion.

10. A rotor as described in claim 9, wherein the stud bolt has a flange portion between the first portion and the second portion in the axial direction, the flange portion being wider in the radial direction than the first portion and the second portion; the shaft body has an accommodating recess recessed from the shaft end face toward the second side in the axial direction and capable of accommodating the flange portion; the flange portion has a flange portion contact surface facing the second side in the axial direction; the accommodating recess has a recess bottom surface facing the first side in the axial direction; and the stud bolt is connected to the shaft body with the flange portion contact surface abutting the recess bottom surface.

11. A rotary machine comprising: a rotor according to claim 1; and a casing that covers the rotor from the outside in the radial direction.

12. A rotor assembling method as set forth in claim 1, comprising the steps of: restricting circumferential rotation of the shaft about the axis of the shaft, inserting the protrusion into the through hole, and connecting the adapter flange to the shaft; and fastening the nut onto the first screw shaft.

13. A method for disassembling a rotor as described in claim 1, comprising the steps of: removing the nut from the first screw shaft while restricting circumferential rotation of the shaft relative to the axis of the shaft; and removing the adapter flange from the shaft and pulling out the protruding portion from the through hole.

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