Rotor and rotating machine equipped therewith

Abstract

The present invention provides a rotor that can properly transmit torque between the core and the shaft, regardless of the ambient temperature. [Solution] The squirrel-cage rotor of the present invention comprises a shaft, a cylindrical core made of laminated electromagnetic steel plates having an opening in which the shaft is placed, a torque transmission plate having an opening in which the shaft is placed, and fixing means for fixing the core and the torque transmission plate. The coefficient of thermal expansion of the torque transmission plate is greater than or equal to the coefficient of thermal expansion of the shaft and less than the coefficient of thermal expansion of the core. The outer surface of the shaft and the inner surface of the opening in the torque transmission plate are in contact, and a gap is formed between the outer surface of the shaft and the inner surface of the opening in the core.

Description

Technical Field

[0001] The present invention relates to a rotor and a rotating machine including the same, for example.

Background Art

[0002] Conventionally, as a cage-type rotor 501 of a rotating machine, as shown in FIG. 14, there is known one having a shaft (rotating shaft) 510, a cylindrical core 520 disposed on the outer peripheral side of the shaft 510, conductor bars 561 embedded in a plurality of slots 521 formed in the outer peripheral portion of the core 520, and end rings 562 connecting the conductor bars 561 at both ends of the core 520. In the cage-type rotor 501, the shaft 510 and the core 520 need to rotate integrally, and for example, they are press-fitted with an appropriate interference fit at the environmental temperature during use. When the interference fit is appropriate, the generated stress can be made smaller than the allowable value while ensuring the surface pressure required for torque transmission.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the cage-type rotor 501, the core 520 and the shaft 510 are generally formed of different materials, and in that case, the linear expansion coefficient of the core 520 and the linear expansion coefficient of the shaft 510 are different. For example, in a cage-type rotor 501 in which the core 20 is formed of an iron electromagnetic steel sheet and the shaft 510 is formed of stainless steel, when the environmental temperature is extremely high or low, the difference between the deformation amount of the core and the deformation amount of the shaft becomes very large, and there is a problem that the interference fit between the core 520 and the shaft 510 becomes excessive or insufficient.

[0005] For example, if the outer diameter of the shaft 510 is larger than the inner diameter of the core 520, the interference fit becomes excessive, leading to excessive stress and damage to both the core 520 and the shaft 510. Conversely, if the inner diameter of the core 520 is larger than the outer diameter of the shaft 510, the interference fit becomes insufficient, preventing the surface pressure necessary for torque transmission from being secured, causing the shaft 510 to rotate relative to the core 520. Furthermore, if a gap is formed between the core 520 and the shaft 510, the surface pressure necessary for torque transmission cannot be secured, causing the shaft 510 to rotate relative to the core 520, and the core 520's center position cannot be maintained, resulting in abnormal vibration. To resolve these issues, it is necessary to set the interference fit considering the coefficients of thermal expansion of both the core material and the shaft material, but this is extremely difficult.

[0006] This invention was made in view of these problems, and its main objective is to provide a rotor and a rotating machine equipped therewith that can properly transmit torque between the core and the shaft regardless of the ambient temperature. [Means for solving the problem]

[0007] In other words, the rotor of the rotating machine according to the present invention comprises a shaft, a cylindrical core made of laminated electromagnetic steel sheets having an opening in which the shaft is arranged, a torque transmission plate having an opening in which the shaft is arranged, and fixing means for fixing the core and the torque transmission plate, wherein the coefficient of linear expansion of the torque transmission plate is greater than or equal to the coefficient of linear expansion of the shaft and less than the coefficient of linear expansion of the core, the outer circumferential surface of the shaft and the inner surface of the opening of the torque transmission plate are in contact, and a gap is formed between the outer circumferential surface of the shaft and the inner surface of the opening of the core.

[0008] The rotor of the rotating machine according to the present invention comprises a shaft, a cylindrical core made of laminated electromagnetic steel sheets having an opening in which the shaft is arranged, a circular torque transmission plate having an opening in which the shaft is arranged, and fixing means for fixing the core and the torque transmission plate, wherein the coefficient of linear expansion of the torque transmission plate is greater than the coefficient of linear expansion of the core and less than or equal to the coefficient of linear expansion of the shaft, the outer circumferential surface of the shaft and the inner surface of the opening of the torque transmission plate are in contact, and a gap is formed between the outer circumferential surface of the shaft and the inner surface of the opening of the core.

[0009] As a result, because there is a large difference in the coefficient of thermal expansion between the core material and the shaft material, no interference fit is provided between the core and the shaft. Instead, a torque transmission plate made of a material with the same or similar coefficient of thermal expansion as the shaft is added, and the core and shaft are connected via the torque transmission plate. This prevents the interference fit between the core and the shaft from becoming excessive or insufficient, regardless of the ambient temperature, even when there is a large difference in the coefficient of thermal expansion between the core and the shaft, and ensures proper torque transmission between the core and the shaft.

[0010] In the rotor of a rotating machine according to the present invention, the fixing means preferably includes a plurality of slots formed at circumferential intervals on the outer circumference of the core and a plurality of notches formed at circumferential intervals on the outer circumference of the torque transmission plate, in which conductive bars are embedded, and end rings connecting the conductive bars at both ends of the core.

[0011] This prevents excessive or insufficient tension between the core and shaft in a squirrel-cage rotor, regardless of ambient temperature, and ensures proper torque transmission between the core and shaft.

[0012] In the rotor of a rotating machine according to the present invention, the torque transmission plates are preferably arranged at both axial ends of the core.

[0013] This ensures that a gap is reliably formed between the outer surface of the shaft and the inner surface of the core.

[0014] In the rotor of the rotating machine according to the present invention, it is preferable that the shaft and the torque transmission plate are formed of the same material.

[0015] Thereby, the tightening allowance between the shaft and the torque transmission plate can be properly maintained.

[0016] The rotating machine according to the present invention includes any one of the above-described rotors.

[0017] Thereby, it is possible to provide a rotating machine that can prevent the tightening allowance between the core and the shaft from becoming excessive or insufficient regardless of the environmental temperature, and can properly perform torque transmission between the core and the shaft.

Effects of the Invention

[0018] According to the present invention, it is possible to prevent the tightening allowance between the core and the shaft from becoming excessive or insufficient regardless of the environmental temperature, and to properly perform torque transmission between the core and the shaft.

Brief Description of the Drawings

[0019] [Figure 1] It is a perspective sectional view of the cage-type rotor 1 according to the present embodiment. [Figure 2] It is a perspective view of the torque transmission plate 50. [Figure 3] It is a perspective view of the cage-type rotor 1 of FIG. 1. [Figure 4] It is a sectional view of the cage-type rotor 1 of FIG. 1. [Figure 5] It is a flowchart showing the procedure for manufacturing the cage-type rotor 1 of FIG. 1. [Figure 6] It is a plan view of the torque transmission plate 150 of the cage-type rotor 101 of the first modified example. [Figure 7] It is a perspective view of the cage-type rotor 101 of the first modified example. [Figure 8] It is a sectional view of the cage-type rotor 101 of the first modified example. [Figure 9]This is a plan view of the torque transmission plate 250 of the second modified cage rotor 201. [Figure 10] This is a perspective view of the second modified example of the cage rotor 201. [Figure 11] This is a cross-sectional view of a second modified example of a cage rotor 201. [Figure 12] This figure illustrates how thermal stress is distributed in the second modified example, the cage rotor 201. [Figure 13] This is a perspective view of the third modified example of the cage rotor 301. [Figure 14] This is a perspective cross-sectional view of a conventional squirrel-cage rotor 501. [Modes for carrying out the invention]

[0020] Hereinafter, the cage rotor 1 of a rotating machine according to an embodiment of the present invention will be described with reference to the drawings.

[0021] The squirrel-cage rotor 1 of this embodiment is used together with a stator that generates a rotating magnetic flux by a three-phase alternating current to constitute a squirrel-cage three-phase induction motor (rotating machine). As shown in Figure 1, the squirrel-cage rotor 1 has a shaft 10, a cylindrical core 20 arranged on the outer circumference of the shaft 10, two torque transmission plates 50 arranged at both ends of the core 20, and conductors 60 that tighten and fix the torque transmission plates 50 to the core 20 in the axial direction.

[0022] The core 20 is made up of multiple layers of electromagnetic steel sheets, which are circular plate-shaped members. A circular opening 20a is formed on the inner circumference of the electromagnetic steel sheets, in which the shaft 10 is placed. Multiple slots 21 are formed on the outer circumference of the core 20 (electromagnetic steel sheets) at intervals in the circumferential direction. The electromagnetic steel sheets are made, for example, mainly of iron, and the average coefficient of linear expansion of the electromagnetic steel sheets is approximately 12 × 10⁻⁶. -6 / K(20~0℃), approx. 9×10 -6 The temperature range is / K (20 to -200℃).

[0023] As shown in Figure 2, the torque transmission plate 50 is a circular plate-shaped member having the same outer diameter as the electromagnetic steel sheet of the core 20. The thickness of the torque transmission plate 50 is greater than the thickness of the electromagnetic steel sheet of the core 20. A circular opening 50a is formed on the inner circumference of the torque transmission plate 50, in which the shaft 10 is positioned. Similar to the core 20, a plurality of notches 51 are formed on the outer circumference of the torque transmission plate 50 at intervals in the circumferential direction. The notches 51 of the torque transmission plate 50 are elongated holes and have substantially the same shape as the slots 21 of the core 20. The average coefficient of linear expansion of the torque transmission plate 50 is greater than the average coefficient of linear expansion of the core 20 and smaller than the average coefficient of linear expansion of the shaft 10, which will be described later, and is made of, for example, stainless steel.

[0024] The conductor 60 has a conductor bar 61 embedded in a slot 21 of the core 20 and a notch 51 of the torque transmission plate 50, and end rings 62 connecting the multiple conductor bars 61 at both ends of the core 20. The conductor bar 61 penetrates the core 20 and the torque transmission plate 50 in the axial direction, and two end rings 62 are positioned at both ends of the core 20. The conductor 60 is made of, for example, aluminum, and the average coefficient of linear expansion of the conductor 60 is approximately 23 × 10⁻¹⁰. -6 / K(20~0℃), approx. 18×10 -6 The temperature range is / K (20 to -200℃). In the squirrel-cage rotor 1, the core 20 is made of iron electromagnetic steel sheet, and the conductor bars 61 and end rings 62 are made of aluminum. The coefficients of linear expansion of the conductor bars 61 and end rings 62 are greater than those of the core 20. In particular, in near-zero temperature environments (liquid gas environments such as liquefied natural gas, liquefied petroleum gas, liquefied nitrogen, and liquefied hydrogen), the conductor bars 61, being rod-shaped, tend to contract axially, and the end rings 62, being annular, tend to contract toward the annular center. Therefore, the conductors 60 press the two torque transmission plates 50 toward the ends of the core 20.

[0025] The shaft 10 has a keyway 31 formed along its axial direction on its outer circumferential surface 10a, and a key 30 is positioned inside the keyway 31, protruding outward from the outer circumferential surface 10a of the shaft 10. A keyway 32 extending in the axial direction is formed on the inner circumferential surface of the core 20 (the upper end of the inner circumferential surface of the core 20 in Figure 1), and a keyway 33 extending in the thickness direction is formed on the inner circumferential surface of the torque transmission plate 50 (the upper end of the inner circumferential surface of the torque transmission plate 50 in Figure 1). With the two torque transmission plates 50 positioned at both ends of the core 20, the key 30 protruding outward from the outer circumferential surface 10a of the shaft 10 engages with the keyway 32 and the keyway 33. Therefore, when the shaft 10 rotates, the rotational torque of the shaft 10 is transmitted to the core 20 via the key 30, causing the shaft 10 and the core 20 to rotate together. The shaft 10 is made of, for example, stainless steel, and the coefficient of linear expansion of the shaft 10 is approximately 15 × 10 -6 / K(20~0℃), approx. 13×10 -6 The temperature range is / K (20 to -200℃).

[0026] Figure 3 is a perspective view of the squirrel-cage rotor 1, but the shaft 10, conductor 60, and key 30 are not shown. As shown in Figure 3, with the two torque transmission plates 50 positioned at both ends of the core 20, the slots 21 of the core 20 and the notches 51 of the torque transmission plates 50 are located at the same position. The radially inner end 21a of the slot 21 and the radially inner end 51a of the notch 51 stacked with the slot 21 are located at the same position in the radial direction.

[0027] The inner diameter of the opening 50a of the torque transmission plate 50 is smaller than the inner diameter of the opening 20a of the electrical steel sheet of the core 20. As shown in Figure 3, when the two torque transmission plates 50 are placed at both ends of the core 20, the inner surface of the opening 50a of the torque transmission plate 50 is positioned radially inward from the inner surface of the opening 20a of the electrical steel sheet of the core 20.

[0028] Therefore, when the shaft 10 is press-fitted into the opening 20a of the electrical steel sheet of the core 20 and the openings 50a of the two torque transmission plates 50, as shown in Figures 1 and 4, the outer circumferential surface 10a of the shaft 10 and the inner surface of the opening 50a of the torque transmission plate 50 are in contact, while a gap T is formed between the outer circumferential surface 10a of the shaft 10 and the inner surface (inner circumferential surface) of the opening 20a of the electrical steel sheet of the core 20. The gap T is formed over almost the entire circumference of the inner surface (inner circumferential surface) of the opening 20a of the core 20.

[0029] The manufacturing method of the cage rotor 1 of this embodiment will be described with reference to Figure 5.

[0030] (Step S1) A core 20 is created by laminating multiple electrical steel sheets.

[0031] (Step S2) Two torque transmission plates 50 are placed at each end of the core 20.

[0032] (Step S3) The core 20 and the two torque transmission plates 50 are cast from aluminum, and the core 20 and the two torque transmission plates 50 are integrally molded to create a core-torque transmission plate assembly. In the core-torque transmission plate assembly, the core 20 and the two torque transmission plates 50 are integrally fixed by a conductor 60.

[0033] (Step S4) The core-torque transmission plate assembly is shrink-fitted (press-fitted) onto the shaft 10.

[0034] (Step S5) The cage rotor 1, in which the shaft 10 is positioned within the core-torque transmission plate assembly, is completed.

[0035] In the cage rotor 1 of this embodiment, when the core-torque transmission plate assembly is shrink-fitted (press-fitted) onto the shaft 10, the shaft 10 and the torque transmission plate 50 are press-fitted with an appropriate interference fit at the ambient temperature during use. As a result, the shaft 10 and the core-torque transmission plate assembly rotate as a single unit.

[0036] In the cage rotor 1 of this embodiment, the torque transmission plate 50 is made of the same material as the shaft 10, and the coefficient of linear expansion of the torque transmission plate 50 is the same as that of the shaft 10. Therefore, even when the ambient temperature is extremely high or low, the difference between the deformation of the shaft 10 and the deformation of the torque transmission plate 50 is very small, and the interference fit between the shaft 10 and the torque transmission plate 50 will not be excessive or insufficient. In other words, because the inner diameter of the torque heating plate 50 follows the change in the outer diameter of the shaft 10 during temperature changes, the interference fit between the shaft 10 and the torque heating plate 50 does not change or the amount of change is suppressed. Also, because there is a gap T between the core 20 and the shaft 10, the interference fit between the core 20 and the shaft 10 will not be excessive or insufficient.

[0037] The cage rotor 1 of this embodiment comprises a shaft 10, a cylindrical core 20 made of laminated electromagnetic steel sheets having an opening 20a in which the shaft 10 is placed, a torque transmission plate 50 having an opening 51a in which the shaft 10 is placed, and a conductor 60 (fixing means) that fixes the core 20 and the torque transmission plate 50. The coefficient of thermal expansion of the torque transmission plate 50 is greater than or equal to the coefficient of thermal expansion of the shaft 10 and less than the coefficient of thermal expansion of the core 20. The outer circumferential surface 10a of the shaft 10 and the inner surface of the opening of the torque transmission plate 50 are in contact, and a gap T is formed between the outer circumferential surface 10a of the shaft 10 and the inner surface of the opening 20a of the core 20.

[0038] As a result, because there is a large difference in the coefficient of thermal expansion between the core material and the shaft material, no interference fit is provided between the core 20 and the shaft 10. Instead, a torque transmission plate 50 made of a material with the same or similar coefficient of thermal expansion as the shaft 10 is added, and the core 20 and the shaft 10 are connected via the torque transmission plate 50. This prevents the interference fit between the core 20 and the shaft 10 from becoming excessive or insufficient, regardless of the ambient temperature, even when there is a large difference in the coefficient of thermal expansion between the core 20 and the shaft 10, and allows for proper torque transmission between the core 20 and the shaft 10.

[0039] In the cage rotor 1 of this embodiment, the conductor 60 has a plurality of slots 21 formed at circumferential intervals on the outer circumference of the core 20 and a plurality of notches 51 formed at circumferential intervals on the outer circumference of the torque transmission plate 50, embedded in the conductor bars 61, and end rings 62 that connect the conductor bars 61 at both ends of the core 20.

[0040] In the cage rotor 1 of this embodiment, it is possible to prevent the overlap between the core 20 and the shaft 10 from becoming excessive or insufficient, regardless of the ambient temperature, and to properly transmit torque between the core 20 and the shaft 10.

[0041] In the cage rotor 1 of this embodiment, the torque transmission plates 50 are arranged at both axial ends of the core 20.

[0042] This ensures that a gap is reliably formed between the outer surface of the shaft 10 and the inner surface of the core 20.

[0043] In the cage rotor 1 of this embodiment, the shaft 10 and the torque transmission plate 50 are made of the same material.

[0044] This makes it possible to properly maintain the tension between the shaft 10 and the torque transmission plate 50.

[0045] The rotating machine according to the present invention is provided on any of the rotors 1 described above.

[0046] This makes it possible to provide a rotor that prevents the interference fit between the core 20 and the shaft 10 from becoming excessive or insufficient, regardless of the ambient temperature, and that enables proper torque transmission between the core 20 and the shaft 10.

[0047] However, the present invention is not limited to the embodiments described above.

[0048] In the above embodiment, the torque transmission plate 50 had the same outer diameter as the electromagnetic steel sheet of the core 20 and a notch 51 with the same shape as the slot 21 of the core 20. However, the shape of the torque transmission plate of the present invention is not limited to that.

[0049] (First variation) Figure 6 is a plan view of the torque transmission plate 150 of the first modified cage rotor 101. Figure 7 is a perspective view of the cage rotor 101, but the shaft 10, conductor 60, and key 30 are not shown. Figure 8 is a cross-sectional view of the cage rotor 101.

[0050] The first modified cage rotor 101, as shown in Figures 6 and 7, has a torque transmission plate 150 smaller than the outer diameter of the electromagnetic steel sheet of the core 20. An opening 150a is formed on the inner circumference of the torque transmission plate 150, where the shaft 10 is positioned. On the outer circumference of the torque transmission plate 150, a plurality of notches 151 are formed at intervals in the circumferential direction, similar to the slots 21 of the core 20. The notches 151 have a length of approximately half the radial length of the slots 21 and are formed in a concave shape from the outer circumference of the torque transmission plate 150 toward the inside. When two torque transmission plates 150 are placed at both ends of the core 20, the notches 151 of the torque transmission plate 150 are positioned at the same location as the radially inner portion of the slots 21 of the core 20. The radially inner end 21a of the slot 21 and the radially inner end 151a of the notch 151 stacked with the slot 21 are positioned at the same location in the radial direction.

[0051] When the shaft 10 is press-fitted into the opening 20a of the electromagnetic steel sheet of the core 20 and the openings 150a of the two torque transmission plates 150, as shown in Figure 8, the outer surface 10a of the shaft 10 and the inner surface of the opening 150a of the torque transmission plate 150 come into contact, while a gap T is formed between the outer surface of the shaft 10 and the inner surface of the opening 20a of the electromagnetic steel sheet of the core 20.

[0052] In the first modified cage rotor 101, the torque transmission plate 150 is made of the same material as the shaft 10, and the coefficient of linear expansion of the torque transmission plate 150 is the same as that of the shaft 10. Therefore, even when the ambient temperature is extremely high or low, the difference between the deformation of the shaft 10 and the deformation of the torque transmission plate 150 is very small, and the interference fit between the shaft 10 and the torque transmission plate 50 will not be excessive or insufficient. In other words, because the inner diameter of the torque heating plate 150 follows the change in the outer diameter of the shaft 10 during temperature changes, the interference fit between the shaft 10 and the torque heating plate 150 does not change or the amount of change is suppressed. Also, because there is a gap T between the core 20 and the shaft 10, the interference fit between the core 20 and the shaft 10 will not be excessive or insufficient.

[0053] (Second variation) Figure 9 is a plan view of the torque transmission plate 250 of the second modified cage rotor 201. Figure 10 is a perspective view of the cage rotor 201, but the shaft 10, conductor 60, and key 30 are not shown. Figure 11 is a cross-sectional view of the cage rotor 201.

[0054] The second modified cage rotor 201, as shown in Figures 9 and 10, has a torque transmission plate 250 that is smaller than the outer diameter of the electromagnetic steel sheet of the core 20 (it is the same as the outer diameter of the torque transmission plate 150 of the first modified cage rotor 101). An opening 250a is formed on the inner circumference of the torque transmission plate 250, where the shaft 10 is positioned, as shown in Figure 9. The torque transmission plate 250 has a plurality of notches 251 formed at intervals in the circumferential direction, similar to the slots 21 of the core 20. The notches 251 are formed in a concave shape extending inward from the outer circumference of the torque transmission plate 250, similar to the notches 151 of the torque transmission plate 150 of the first modified example. The depth of the concave shape of the notches 251 extending radially inward is greater than the depth of the concave shape of the notches 151 extending radially inward. Therefore, when the two torque transmission plates 250 are positioned at both ends of the core 20, the notches 251 of the torque transmission plates 250 are positioned at the same location as the radially inner portion of the slot 21 of the core 20. The radially inner end 251a of the notch 251 is positioned radially inward from the radially inner end 21a of the slot 21 that is formed with the notch 251.

[0055] When the shaft 10 is press-fitted into the opening 20a of the electrical steel sheet of the core 20 and the openings 250a of the two torque transmission plates 250, as shown in Figure 11, the outer surface of the shaft 10 and the inner surface of the opening 250a of the torque transmission plate 250 come into contact, while a gap T is formed between the outer surface of the shaft 10 and the inner surface of the opening 20a of the electrical steel sheet of the core 20.

[0056] In the second modified cage rotor 201, the torque transmission plate 250 is made of the same material as the shaft 10, and the coefficient of linear expansion of the torque transmission plate 250 is the same as that of the shaft 10. Therefore, even when the ambient temperature is extremely high or low, the difference between the deformation of the shaft 10 and the deformation of the torque transmission plate 250 is very small, and the interference fit between the shaft 10 and the torque transmission plate 250 does not become excessive or insufficient. In other words, because the inner diameter of the torque heating plate 250 follows the change in the outer diameter of the shaft 10 during temperature changes, the interference fit between the shaft 10 and the torque heating plate 250 does not change or the amount of change is suppressed. Also, because there is a gap T between the core 20 and the shaft 10, the interference fit between the core 20 and the shaft 10 does not become excessive or insufficient.

[0057] Figure 12(a) shows a part of the conventional squirrel-cage rotor 501 shown in Figure 14. In the squirrel-cage rotor 501, when the core 520 is made of iron electromagnetic steel sheet and the conductor bars 561 and end rings 562 are made of aluminum, the coefficients of linear expansion of the conductor bars 561 and end rings 562 are greater than those of the core 520. In particular, in near-zero temperature environments (liquid gas environments such as liquefied natural gas, liquefied petroleum gas, liquefied nitrogen, and liquefied hydrogen), the conductor bars 561, being rod-shaped, tend to contract axially, and the end rings 562, being annular, tend to contract toward the center of the annulus. At that time, the core 520 also contracts, but due to the properties of the material, its rate of change is smaller than that of the conductor bars 561 and end rings 562. Therefore, in near-zero temperature environments, thermal stress due to the difference in the coefficients of linear expansion of each material occurs locally (part 503a in Figure 12(a)).

[0058] In contrast, Figure 12(b) shows a part of the second modified squirrel-cage rotor 201 shown in Figure 11, in which the torque transmission plate 250 is positioned on the end face of the core 20. As shown in Figure 12(b), radially inward from the slot 21 of the core 20, the torque transmission plate 250 protrudes axially outward from the end face of the core 20, so a step portion N is formed at the boundary between the end face of the core 20 and the torque transmission plate 250. In the squirrel-cage rotor 201, as with the squirrel-cage rotor 501, especially in near-zero temperature environments (liquid gas environments such as liquefied natural gas, liquefied petroleum gas, liquefied nitrogen, and liquefied hydrogen), the conductor bar 61 tends to contract axially, and the end ring 562 tends to contract toward the annular center. In the case of the squirrel-cage rotor 201, a stepped portion N is formed at the boundary between the end face of the core 20 and the torque transmission plate 250. As a result, the surface of the conductor bar 61 that receives the contraction force is divided into two locations (the end face of the core 20 and the end face of the torque transmission plate 250), and the contraction force of the end ring 62 is received by the wide surface of the end face of the torque transmission plate 250. Therefore, in an environment near cryogenic temperatures, the thermal stress due to the difference in the coefficient of linear expansion of each material is distributed to two locations (the two parts 3a in Figure 12(b)).

[0059] However, the present invention is not limited to the embodiments described above.

[0060] The torque transmission plate 50 in the above embodiment, the torque transmission plate 150 in the first modified example, and the torque transmission plate 250 in the second modified example are made of the same material as the shaft 10, and their coefficient of thermal expansion is the same as that of the shaft 10, but is not limited to this. For example, the torque transmission plates 50, 150, and 250 may be made of a material whose coefficient of thermal expansion is greater than or equal to that of the shaft 10 and less than that of the core 20. Alternatively, the torque transmission plates 50, 150, and 250 may be made of a material whose coefficient of thermal expansion is greater than that of the core 20 and less than or equal to that of the shaft 10.

[0061] In the above embodiment, the squirrel-cage rotor 1 was manufactured by shrink-fitting (press-fitting) the core-torque transmission plate assembly onto the shaft 10 while it was heated, but the invention is not limited to this. For example, the squirrel-cage rotor 1 may be manufactured by shrink-fitting (press-fitting) the core-torque transmission plate assembly at room temperature onto the shaft 10 while it is cooled.

[0062] In the above embodiment, the conductor 60 (conductor bar 61 and end ring 62) is a fixing means that fastens and secures the two torque transmission plates 50 and the core 20 in the axial direction, but it is not limited to this. In the present invention, the fixing means for fixing the two torque transmission plates 50 and the core 20 is not limited to the conductor 60 that fastens and secures the two torque transmission plates 50 and the core 20 in the axial direction. The fixing means for fixing the two torque transmission plates 50 and the core 20 may have other configurations.

[0063] In the above embodiment, two torque transmission plates 50 were arranged at both ends of the core 20, but the number and arrangement of the torque transmission plates 50 are not limited thereto. For example, in the third modified squirrel-cage rotor 301, as shown in Figure 13, two torque transmission plates 50 are arranged at both ends of the core 20, and one torque transmission plate 50 is arranged in the axial center of the core 20. In the squirrel-cage rotor 301, the core 20 is formed by two cores 20a. The torque transmission plates 50 of the present invention only need to be arranged between the end faces of the end rings 62.

[0064] In the above embodiment, the key 30 is positioned between the shaft 10 and the core 20 and torque transmission plate 50, but it is not limited to this. In the present invention, the key 30 does not have to be positioned between the core 20 and the torque transmission plate 50.

[0065] Although the above embodiment described an aluminum squirrel-cage rotor, the present invention is not limited thereto. The present invention is applicable to all rotors that use a core, such as copper squirrel-cage rotors, wound rotors, permanent magnet rotors, and generator rotors.

[0066] Furthermore, the specific configuration of each part is not limited to the above embodiment, and the present invention Various modifications are possible as long as they do not deviate from the original purpose. [Explanation of symbols]

[0067] 1. Cage-type rotor 10 shafts 10a Outer surface of the shaft 20 cores 20a opening 21 slots 50 Torque transmission plate 50a opening 51 Notches 60 Conductor (fixing means) 61 Conductor Bars 62 End Rings

Claims

1. The shaft and A cylindrical core made of laminated electromagnetic steel sheets having an opening in which the shaft is arranged, A torque transmission plate having an opening in which the shaft is arranged, The system includes fixing means for fixing the core and the torque transmission plate, The coefficient of linear expansion of the torque transmission plate is greater than or equal to the coefficient of linear expansion of the shaft and less than the coefficient of linear expansion of the core. A rotor for a rotating machine, characterized in that the outer circumferential surface of the shaft and the inner surface of the opening of the torque transmission plate are in contact, and a gap is formed between the outer circumferential surface of the shaft and the inner surface of the opening of the core.

2. The shaft and A cylindrical core made of laminated electromagnetic steel sheets having an opening in which the shaft is arranged, A circular torque transmission plate having an opening in which the shaft is arranged, The system includes fixing means for fixing the core and the torque transmission plate, The coefficient of linear expansion of the torque transmission plate is greater than the coefficient of linear expansion of the core and less than or equal to the coefficient of linear expansion of the shaft. A rotor for a rotating machine, characterized in that the outer circumferential surface of the shaft and the inner surface of the opening of the torque transmission plate are in contact, and a gap is formed between the outer circumferential surface of the shaft and the inner surface of the opening of the core.

3. The aforementioned fixing means is A plurality of slots formed at circumferential intervals on the outer periphery of the core and a plurality of notches formed at circumferential intervals on the outer periphery of the torque transmission plate, in which a conductor bar is embedded. The rotor of a rotating machine according to claim 1 or 2, characterized in that it has end rings connecting the conductor bars at both ends of the core.

4. The rotor of the rotating machine according to claim 1 or 2, characterized in that the torque transmission plates are arranged at both axial ends of the core, respectively.

5. The rotor of a rotating machine according to claim 1 or 2, characterized in that the shaft and the torque transmission plate are formed from the same material.

6. A rotating machine comprising a rotor according to any one of claims 1 to 5.

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