Rotor of rotating machine

Abstract

To provide a rotor of a rotary machine capable of improving torque in the rotary machine.SOLUTION: In a rotor 3 of a motor 1, which is fixed to a rotary shaft 2 extending around a predetermined axis A and along the axis A in a state where the rotary shaft 2 penetrates the rotary shaft 2, and in which a stator 4 is arranged on an outer side in a radial direction, the stator 4 has a stator core 11 constituted of a predetermined metal material, and the rotor 3 has a rotor core 5 constituted entirely or partially of a high material made of a predetermined metal material having a higher saturation magnetic flux density than that of the stator core 11.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a rotor for a rotating machine such as an electric motor or a generator, and more particularly to the structure of a rotor core around which coils are wound and permanent magnets are embedded. [Background technology]

[0002] A conventional wound-field motor having a rotor with a coil wound around a rotor core is known, for example, from the one described in Patent Document 1. This motor includes a rotor and a cylindrical stator disposed radially outside the rotor. The rotor core of the rotor and the stator core of the stator are made of the same electromagnetic steel sheet. The rotor core has multiple salient poles, each of which has a coil wound around it. While it is possible to increase the magnetic flux density of each salient pole of the rotor by increasing the current applied to the rotor coil, magnetic saturation due to the material characteristics of the rotor core may prevent sufficient magnetic flux density from being obtained at each salient pole. Therefore, in the wound-field motor, permanent magnets are disposed between the heads of adjacent salient poles of the rotor core on the tip side to mitigate magnetic saturation at each salient pole. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-228460 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the above motor, although the provision of permanent magnets in the rotor reduces the field magnetic flux generated by the coils of each salient pole, thereby mitigating magnetic saturation, the reduction in field magnetic flux also reduces the output torque of the motor.

[0005] The present invention has been made to solve the above-mentioned problems, and has an object to provide a rotor for a rotating machine that can improve torque in the rotating machine. [Means for solving the problem]

[0006] In order to achieve the above object, the invention of claim 1 is a rotor of a rotating machine that is fixed to a rotating shaft that is centered on a predetermined axis and extends along the axis, with the rotating shaft penetrating the rotating shaft, and that has a stator disposed radially outward, wherein the stator has a stator core made of a predetermined metal material, and the rotor has a rotor core that is made entirely or partially of a high Bs material made of the predetermined metal material having a higher saturation magnetic flux density than the stator core.

[0007] According to this configuration, in a rotating machine including the rotor and stator, the rotor core of the rotor is entirely or partially made of a high-Bs material made of a predetermined metallic material having a higher saturation magnetic flux density than the stator core of the stator. As a result, in a rotating machine including the rotor, the magnetic flux density of the salient poles formed in the rotor can be increased compared to conventional rotating machines in which the rotor core is made of the same metallic material as the stator core, such as an electromagnetic steel sheet, and the output torque of the rotating machine can be improved.

[0008] The invention of claim 2 is characterized in that, in the rotor of the rotating machine described in claim 1, the rotor core has a rotating shaft fixing portion fixed to the rotating shaft with the rotating shaft passing through it, and a plurality of teeth protruding radially outward from this rotating shaft fixing portion and arranged at predetermined angles circumferentially around the axis, with a coil wound around each tooth, and only each tooth is made of high Bs material.

[0009] With this configuration, only the teeth of the rotor core are made of high Bs material, which reduces the manufacturing cost of the rotor compared to when the entire rotor core is made of a relatively expensive high Bs material. Also, since high Bs material is provided on each tooth of the rotor around which the coil is wound, it is possible to ensure that the field magnetic flux of the salient poles is improved by each tooth.

[0010] The invention of claim 3 is characterized in that, in the rotor of the rotating machine described in claim 2, each tooth has a through hole extending along the axis, and a high Bs material is inserted and embedded in the through hole.

[0011] According to this configuration, high Bs materials are inserted and embedded in the above-mentioned through holes provided in each tooth of the rotor core. Therefore, when manufacturing the rotor, multiple high Bs materials can be easily attached to the rotor core simply by inserting them into the corresponding through holes, and the multiple high Bs materials can be held stably in the rotor core when the rotor rotates.

[0012] The invention of claim 4 is characterized in that, in the rotor of a rotating machine described in any one of claims 1 to 3, the rotor further has a plurality of permanent magnets arranged along the circumferential direction of the rotor core.

[0013] With this configuration, multiple permanent magnets are arranged along the circumferential direction of the rotor core, thereby increasing the field magnetic flux of the rotor generated by passing current through these permanent magnets and the coils wound around each tooth.

[0014] The invention of claim 5 is characterized in that, in the rotor of the rotating machine described in claim 4, the rotor core has a plurality of magnet embedding holes in which a plurality of permanent magnets are respectively embedded, and the high Bs material is provided in a predetermined area around the plurality of magnet embedding holes other than the first narrow portions between each of the plurality of magnet embedding holes and the outer periphery of the rotor core and the second narrow portions between adjacent magnet embedding holes.

[0015] According to this configuration, leakage magnetic flux from the field magnetic flux generated by the permanent magnet embedded in the magnet embedding hole that passes through the first and second narrow portions can be suppressed, and as a result, the field magnetic flux generated by the rotor can be increased. [Brief explanation of the drawings]

[0016] [Figure 1] 1A and 1B are diagrams for explaining a motor to which a rotor according to an embodiment of the present invention is applied, in which (a) is a schematic cross-sectional view of the motor cut perpendicular to the rotation axis, and (b) is a partial cross-sectional view of the motor shown in (a) enlarged with a central angle of 45 degrees. [Figure 2] 1(b) is a partial cross-sectional view similar to FIG. 1(b) for explaining a motor including a rotor according to a first embodiment, showing a state in which the entire rotor core is made of a high Bs material. [Figure 3] 1(b) is a diagram for explaining a motor equipped with a rotor according to a second embodiment, and is a partial cross-sectional view similar to FIG. 1(b), where (a) shows a state in which the entire tooth body portion of each tooth of the rotor core is made of a high Bs material, and (b) is a modified example of (a), showing a state in which a portion of the tooth body portion of each tooth of the rotor core is made of a high Bs material. [Figure 4] 1(b) is a diagram for explaining a motor including a rotor according to a third embodiment, and is a partial cross-sectional view similar to FIG. 1(b), showing a state in which a high Bs material is embedded in each tooth of the rotor core. [Figure 5] 6 is a graph showing an example of the operation results of a motor as an example, which is provided with the rotor of the first embodiment, and the operation results of a motor as a comparative example. [Figure 6] FIG. 10 is a diagram for explaining a rotor according to a fourth embodiment, and is a partial cross-sectional view showing the rotor with a central angle of 90 degrees. [Figure 7]10A and 10B are diagrams for explaining a rotor according to a fifth embodiment, in which (a) is a partial cross-sectional view of a rotor of a conventional IPM motor with a central angle of 45 degrees, (b) is a diagram showing the field flux and leakage flux in the rotor shown in (a), and (c) shows the rotor shown in (a) in a state where part of the rotor core is made of a high Bs material. DETAILED DESCRIPTION OF THE INVENTION

[0017] A preferred embodiment of the present invention will be described in detail below with reference to the drawings. Fig. 1(a) shows a schematic cross-sectional view of a motor 1 (rotating machine) to which a rotor according to one embodiment of the present invention is applied. As shown in the figure, this motor 1 is a wound-field synchronous motor, and includes a rotor 3 fixed to a rotating shaft 2 centered on and extending along a predetermined axis A with the rotating shaft 2 passing through the rotor 3, and a stator 4 disposed radially outward of the rotor 3.

[0018] The rotating shaft 2 is made of a metal round bar with a predetermined diameter and length, and is rotatably supported by bearings (neither of which is shown) provided in the housing of the motor 1.

[0019] The rotor 3 has a rotor core 5 made of a predetermined metal material and a rotor coil 6 wound around each of teeth 8 of the rotor core 5, which will be described later. The rotor core 5 is formed by laminating metal plates of a predetermined shape in the longitudinal direction of the axis A. Specifically, the rotor core 5 has a rotating shaft fixing portion 7 having an axial hole 7a in the center through which the rotating shaft 2 passes, and a plurality of teeth 8 (eight in FIG. 1(a)) that protrude radially outward from the rotating shaft fixing portion 7 and are arranged at predetermined angle intervals (45 degrees in FIG. 1(a)) around the axis A in the circumferential direction.

[0020] FIG. 1(b) shows an enlarged view of the motor 1 shown in FIG. 1(a) with a central angle of 45 degrees. As shown in FIG. 1(b), the teeth 8 of the rotor 3 have tooth main bodies 8a and tooth heads 8b provided at the tips of the tooth main bodies 8a. The tooth main bodies 8a protrude radially outward from the rotary shaft fixing portion 7 by a predetermined length and are formed to have a predetermined width in the circumferential direction. On the other hand, the tooth heads 8b are formed to be circumferentially longer than the width of the tooth main bodies 8a and have arc-shaped tip surfaces on the radially outer side. The tooth heads 8b of each tooth 8 face the inner circumferential surface of the stator 4 with a gap between them.

[0021] Each tooth 8 configured as above has a rotor coil 6 wound around a tooth main body 8a.

[0022] The stator 4 has a stator core 11 made of a predetermined metal material and a stator coil 12 wound around each of teeth 13 (described later) of the stator core 11. The stator core 11 is formed into a cylindrical shape by laminating annular metal plates in the longitudinal direction of the axis A. The stator core 11 also has a plurality of teeth 13 (48 in FIG. 1(a)) that protrude inward and are arranged circumferentially around the axis A at predetermined angle intervals (7.5 degrees in FIG. 1(a)). As described above, a stator coil 12 is wound around each tooth 13.

[0023] Fig. 2 shows a motor 1 equipped with a rotor 3 according to a first embodiment of the present invention. In the following description, the same components as those in the motor 1 shown in Fig. 1 above will be denoted by the same reference numerals, and detailed description thereof will be omitted.

[0024] As shown in FIG. 2(a), in this motor 1, the entire rotor core 5 of the rotor 3A is made of a high-Bs material, which is a metallic material with a higher saturation magnetic flux density than the stator core 11 of the stator 4. Specifically, the stator core 11 is made of, for example, electromagnetic steel sheets, while the rotor core 5 is made of, for example, permendur, an alloy of iron and cobalt, as a high-Bs material. The saturation magnetic flux density of the electromagnetic steel sheets is, for example, 2.03 T, and the saturation magnetic flux density of the permendur is, for example, 2.37 T. In FIG. 2 (as well as in FIGS. 3, 4, 6, and 7), the portions made of the high-Bs material are indicated by hatching.

[0025] As described above, the motor 1 of the first embodiment is provided with a rotor 3A in which the entire rotor core 5 is made of a high Bs material, and therefore the magnetic flux density of the salient poles formed in each tooth 8 of the rotor 3A can be increased compared to when the entire rotor core 5 is made of the same electromagnetic steel plate as the stator core 11, thereby improving the output torque of the motor 1.

[0026] Fig. 3 shows a motor 1 equipped with a rotor 3 according to a second embodiment of the present invention, in which a portion of a rotor core 5 is made of a high Bs material. Specifically, in a rotor 3B of the motor 1 shown in Fig. 3(a), the entire tooth body portion 8a of each tooth 8 of the rotor core 5 is made of a high Bs material 9A. Note that the portions of the rotor core 5 other than the high Bs material 9A are made of the same metal material (e.g., electromagnetic steel sheet) as the stator core 11.

[0027] 3(b), two high Bs materials 9B, 9B are provided at a distance from each other on both circumferential sides of the tooth main body 8a of each tooth 8 of the rotor core 5. The portions of each tooth main body 8a of the rotor core 5 other than the high Bs materials 9B, 9B, including the area between the high Bs materials 9B, 9B, are made of the same metal material as the stator core 11.

[0028] As described above, in the motor 1 of the second embodiment, only each tooth 8 has high Bs material 9A, so that the manufacturing costs of the rotors 3B and 3C can be suppressed compared to when the entire rotor core 5 is made of a relatively expensive high Bs material, and the magnetic flux density of the salient poles formed by each tooth 8 can be increased.

[0029] Fig. 4 shows a motor 1 equipped with a rotor 3 according to a third embodiment of the present invention, and in this motor 1, a portion of the rotor core 5 is made of a high Bs material, as in the above-described second embodiment. Specifically, as shown in Fig. 4, in a rotor 3D of this motor 1, a high Bs material embedding hole 8c (through hole) is formed in the tooth main body 8a of each tooth 8 of the rotor core 5, extending along the axis A and penetrating the tooth main body 8a, and a high Bs material 9C is inserted and embedded in this high Bs material embedding hole 8c.

[0030] As described above, in the motor 1 of the third embodiment, the high Bs materials 9C are inserted and embedded in the high Bs material embedding holes 8c provided in each tooth 8 of the rotor core 5, thereby achieving the same effects as those of the second embodiment described above. In addition, when manufacturing the rotor 3D, simply inserting the multiple high Bs materials 9C into the corresponding high Bs material embedding holes 8c allows them to be easily attached to the rotor core 5, and the multiple high Bs materials 9C can be stably held in the rotor core 5 when the rotor 3D rotates.

[0031] 5 is a graph showing an example of the operation results of a motor 1 as an example equipped with the rotor 3A of the first embodiment and the operation results of a motor as a comparative example, where the horizontal axis represents the armature current phase and the vertical axis represents torque. As described above, the example shown in FIG. 5 shows the operation results of a motor 1 equipped with the rotor 3A of the first embodiment, i.e., a rotor 3A whose rotor core 5 is entirely made of a high Bs material.

[0032] On the other hand, Comparative Example 1 shown in Figure 5 shows the operation results of a PM motor that uses a permanent magnet in the rotor. Also, Comparative Example 2 shows the operation results of a wound-field motor in which a coil is wound around a rotor core, similar to Motor 1 of the above-mentioned embodiment. Unlike Motor 1 of the embodiment, this wound-field motor has a rotor core entirely made of the same metal material (e.g., electromagnetic steel sheet) as the stator core.

[0033] As described above, the example and comparative example 2 shown in FIG. 5 are both the results of operation of a wound-field motor, and the armature current phase is advanced from the q-axis by a predetermined angle (e.g., 30 degrees) compared to comparative example 1. Furthermore, the example and comparative example 2 are shown with the torque peak of comparative example 1 set to a value of 1.0 pu. The torque peak of comparative example 2 is 0.94 pu, while the torque peak of the example is 1.1 pu. From the above results, it can be seen that motor 1 of the example equipped with rotor 3A has a torque improvement of approximately 9 to 15% compared to the motors of comparative examples 1 and 2 equipped with rotors whose rotor cores do not contain high-Bs material.

[0034] In the first to third embodiments described above, the rotor 3 is not provided with a permanent magnet, but it is also possible to provide a permanent magnet on the rotor 3 as described below.

[0035] 6 shows a rotor 3E according to a fourth embodiment of the present invention with a central angle of 90 degrees. In this rotor 3E, permanent magnets 22 are embedded in each tooth 8 of a rotor core 5, and high Bs material 9D wound around a rotor coil 6A is arranged between adjacent teeth 8, 8 in the circumferential direction.

[0036] Specifically, a magnet embedding hole 8d of a predetermined shape is formed at the radially outer end of each tooth 8 so as to extend along the length of the axis A, and a permanent magnet 22 is inserted and fixed in the magnet embedding hole 8d. In addition, a high Bs material 9D arranged between adjacent teeth 8, 8 is formed in a block shape extending in the radial and length directions of the axis A, and the rotor coil 6A is wound around the high Bs material 9D. Note that the symbol S in Figure 6 denotes an air gap extending along the length of the axis A.

[0037] In the rotor 3E of the fourth embodiment described above, similarly to the first to third embodiments described above, the magnetic flux density of the salient poles due to each tooth 8 can be increased.

[0038] In the first to fourth embodiments described above, the rotor 3 is provided with the rotor coil 6 (6A), but the present invention can also be applied to a rotor 3 that does not have such a coil.

[0039] Figure 7 is a diagram for explaining a rotor 3 according to a fifth embodiment of the present invention, where (a) and (b) show a rotor 30 of a conventional IPM (Interior Permanent Magnet) motor with a central angle of 45 degrees, and (c) shows a rotor 3F of the fifth embodiment.

[0040] 7(a), adjacent magnet embedding holes 24, 24 are formed in predetermined locations on the radially outer side of the rotor core 5, and permanent magnets 23 are inserted and fixed in each magnet embedding hole 24. In this rotor 30, narrow first bridges 25 (first narrow portions) are formed between predetermined locations of each magnet embedding hole 24 and the outer periphery of the rotor core 5, and narrow second bridges 26 (second narrow portions) are formed between the magnet embedding holes 24, 24.

[0041] In the rotor 30 configured as described above, as shown in FIG. 7(b), field magnetic flux (indicated by solid arrows pointing radially outward) is generated by each permanent magnet 23, and leakage magnetic flux (indicated by dashed arrows) is generated in each of the first bridge 25 and the second bridge 26.

[0042] In contrast, in the rotor 3F of this embodiment, as shown in Fig. 7(c), first to third high Bs materials 27A to 27C are arranged in predetermined regions of the rotor core 5. Specifically, in the rotor core 5, the first high Bs material 27A and the second high Bs material 7B are arranged respectively on the radially outer and inner sides of the magnet embedding holes 24, and further, for each pair of adjacent magnet embedding holes 24, 24, a third high Bs material 27C is arranged between each pair of magnet embedding holes 24, 24. In this manner, the first to third high Bs materials 27A to 27C are arranged in regions of the rotor core 5 other than the first bridge 25 and the second bridge 26. The first to third high Bs materials 27A to 27C are fixed to the rotor core 5 by being inserted into high Bs material embedding holes formed in the rotor core 5.

[0043] Unlike the rotor 30, the rotor 3F of the fifth embodiment described above can increase the magnetic flux density while reducing leakage magnetic flux.

[0044] The present invention is not limited to the above-described embodiments and can be embodied in various forms. For example, although the rotor 3 used in an electric motor has been described in each embodiment, the present invention can also be applied to a rotor used in a generator.

[0045] Furthermore, when manufacturing the rotor 3 of each embodiment, it is possible to omit the magnetic annealing process that is generally performed after the rolling process of the material, thereby reducing the manufacturing cost of the rotor 3.

[0046] Furthermore, the detailed configurations of the rotor 3, rotor core 5, and high Bs materials 9A to 9D and 27A to 27C shown in the embodiment are merely examples and can be changed as appropriate within the scope of the present invention. [Explanation of symbols]

[0047] 1. Motor (rotating machine) 2 rotation axes 3 rotors 3A Rotor of First Embodiment 3B Rotor of the second embodiment 3C Rotor of a modified example of the second embodiment 3D Rotor of the third embodiment 3E Rotor of the fourth embodiment 3F Rotor of the fifth embodiment 4 Stator 5 rotor core 6 rotor coil (coil) 6A rotor coil (coil) 7 Rotation shaft fixing part 7a Shaft hole 8 Rotor core teeth 8a Teeth body 8b Teeth head 8c High Bs material buried hole (through hole) 8d Magnet burial hole 9A High Bs material 9B High Bs material 9C High Bs material 9D High Bs material 11 Stator core 12 stator coil 13 Stator core teeth 22 Permanent magnet of the fourth embodiment 23 Permanent magnet of the fifth embodiment 24 Magnet embedding hole of the fifth embodiment 25 First bridge (first narrow part) 26 Second bridge (second narrow part) 27A First high Bs material of the fifth embodiment 27B Second high Bs material of the fifth embodiment 27C Third high Bs material of the fifth embodiment A axis

Claims

1. A rotor of a rotating machine is fixed to a rotating shaft that is centered on a predetermined axis and extends along the axis, with the rotating shaft passing through the rotor, and a stator is disposed radially outward, the stator has a stator core made of a predetermined metal material, The rotor of a rotating machine is characterized in that the rotor has a rotor core that is entirely or partially made of a high Bs material made of a specified metal material having a higher saturation magnetic flux density than the stator core.

2. The rotor core is a rotating shaft fixing portion fixed to the rotating shaft with the rotating shaft passing through; a plurality of teeth, each of which has a coil wound thereon, protruding radially outward from the rotary shaft fixing portion, and arranged at predetermined angles around the axis; It has 2. The rotor for a rotating machine according to claim 1, wherein only each of the teeth is made of the high Bs material.

3. Each of the teeth has a through hole extending along the axis, 3. The rotor for a rotating machine according to claim 2, wherein the high Bs material is inserted and embedded in the through-hole.

4. 4. The rotor for a rotating machine according to claim 1, further comprising a plurality of permanent magnets arranged in a circumferential direction of the rotor core.

5. the rotor core has a plurality of magnet embedding holes in which the plurality of permanent magnets are respectively embedded, 5. The rotor of a rotating machine according to claim 4, wherein the high Bs material is provided in a predetermined region around the plurality of magnet embedding holes other than first narrow portions between each of the plurality of magnet embedding holes and the outer periphery of the rotor core and second narrow portions between adjacent magnet embedding holes.

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