JP4377325B2 - Permanent magnet type rotating electric machine, air compressor and turbine generator - Google Patents

Description

  The present invention relates to a permanent magnet type rotating electrical machine suitable for use in an ultra-high speed variable speed motor or a small turbine generator for driving a compressor or the like, an air compressor using the same, and a turbine generator.

In the air compressor, the rotational speed is set to 40000 [rpm] or more to reduce the size and weight of the drive motor and the entire compressor. A permanent magnet is used for the rotor of the drive motor. The outer periphery of the rotor is protected by a reinforcing material so that the permanent magnet is not damaged by the centrifugal force accompanying high-speed rotation.
Japanese Patent Laid-Open No. 10-248185 discloses a rotation in which a permanent magnet is attached via a stator having an armature winding and a cylindrical member fixed to a rotating shaft that rotates inside thereof, and the outer periphery thereof is covered with a reinforcing material. A permanent magnet type rotating electrical machine having a child is disclosed. Here, a non-magnetic porous cylindrical member having air holes is provided on the outer periphery of the rotating shaft, a laminated electromagnetic steel sheet is provided on the outer periphery, and a segment magnet is attached on the outer periphery. This magnet has a structure in which a reinforcing member made of carbon fiber or the like is disposed on the outer periphery of the magnet.

In the above prior art, a technique for reinforcing the attachment of a permanent magnet to a rotor that rotates at high speed has been proposed, but the strength of the rotating shaft becomes an important factor when the demand for high-speed rotation in an air compressor or the like increases. . If the strength of the rotating shaft is not sufficient, it will not be able to withstand large vibrations at the resonance point, and the vibration will increase, causing contact with the stator or destruction. Moreover, even if it is going to make a rotating shaft thick and ensure intensity | strength, the centrifugal force by dead weight will also increase and high-speed rotation will become difficult.
An object of the present invention is to provide a permanent magnet type rotating electrical machine that is small and light and can stably rotate at a high speed.
Another object of the present invention is to provide a permanent magnet type rotating electrical machine that is excellent in productivity and capable of rotating at high speed stably.
Another object of the present invention is to provide an air compressor that is small and light and has excellent productivity.
Furthermore, another object of the present invention is to provide a turbine generator that is small and light and has excellent productivity.
In one aspect of the present invention, there is provided a permanent magnet type rotating electric machine including a stator having an armature winding and a rotor having a permanent magnet attached to a rotating shaft rotating inside thereof via a cylindrical member of a magnetic material. The rotating shaft is made of a non-magnetic material.
In another aspect of the present invention, in a permanent magnet type rotating electric machine having a stator with armature winding and a rotor having a permanent magnet attached to a rotating shaft rotating inside the stator, the rotating shaft is a non-magnetic material. In addition, the permanent magnet is attached to the rotating shaft with a magnetic cylindrical member interposed therebetween.
In another aspect of the present invention, the relationship between the thickness of the cylindrical member of the magnetic body and the thickness of the rotating shaft is clarified with respect to the required thickness of the permanent magnet and the utilization factor.
The magnetic flux generated by the permanent magnet passes through the magnetic path by the cylindrical member of the magnetic material instead of the rotating shaft inside the permanent magnet to form a permanent magnet type rotating electrical machine. By using a non-magnetic rotating shaft as the rotating shaft, the material of the rotating shaft is not limited, it is easy to ensure strength, and a small and lightweight permanent magnet type rotating electrical machine that can withstand high-speed rotation can be obtained.
In another aspect of the present invention, in an air compressor including a permanent magnet electric motor and a compressor coupled to the rotating shaft of the electric motor, the rotor of the electric motor and the rotating shaft connected to the blade of the compressor are integrated. The non-magnetic material is formed into a non-magnetic material.
Still another aspect of the present invention is a turbine generator including a permanent magnet generator, a compressor and a turbine connected to a shaft of the generator, a rotor of the generator, a blade of the compressor, The rotating shaft connected to the blades of the turbine is a non-magnetic material formed integrally.
Thereby, the air compressor and turbine generator provided with the small and lightweight permanent magnet type rotary electric machine which enables the stable high-speed rotation are realizable.
Other objects and features of the present invention will become apparent from the embodiments described below.

  FIG. 1 is an axial sectional view showing a basic structure of a permanent magnet type rotating electrical machine according to an embodiment of the present invention, FIG. 2 is a sectional view taken along line II-II in FIG. 1, and FIG. Fig. 4 is a schematic diagram showing radial magnetization of a permanent magnet according to an embodiment, Fig. 4 is a schematic diagram showing hullback magnetization of a permanent magnet according to another embodiment of the present invention, and Fig. 5 is a cylinder according to one embodiment of the present invention. FIG. 6 is a graph of measured values showing the ratio of induced electromotive force to cylindrical member thickness / rotating shaft radius according to one embodiment of the present invention, and FIG. FIG. 8 is a graph of actually measured values showing the induced electromotive force ratio with respect to the thickness of the cylindrical member showing the embodiment of the invention. FIG. 8 is an actually measured value showing the ratio of induced electromotive force with respect to the thickness of the cylindrical member / rotating shaft radius according to another embodiment of the present invention. FIG. 9 shows a schematic structure of a turbine generator according to an embodiment of the present invention. It is to axial sectional view.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a radial sectional view schematically showing a permanent magnet type rotating electrical machine according to an embodiment of the present invention, and FIG. 2 is a sectional view taken along the line II-II in FIG. In these drawings, the stator 10 includes a three-phase winding 13 wound in a plurality of slots 12 provided in the stator yoke 11.
On the other hand, the rotor 20 has a configuration in which a permanent magnet 23 is attached to a non-magnetic rotating shaft 21 via a magnetic cylindrical member 22 and the outside thereof is reinforced by a reinforcing member 24. The thickness PMt of the permanent magnet 23 in this embodiment is 6.5 [mm]. The non-magnetic rotating shaft 21 is made of a nonmagnetic material having high strength such as Inconel, for example, “In718”, and in this embodiment, the radius SHt is 8 [mm]. The cylindrical member 22 is divided into a first cylindrical member 221 and a second cylindrical member 222 for assembly reasons, and the two are overlapped between the permanent magnet 23 and the non-magnetic rotating shaft 21. A desired thickness CCt = 24 [mm] is ensured.
In assembly, first, the permanent magnet 23 and the reinforcing material 24 are attached to the outer periphery of the relatively thin first cylindrical member 221. Specifically, in order to align the axial direction of the permanent magnet 23 and to fix and hold the permanent magnet 23 and the reinforcing material 24, the holding ring 251 extends to the back side (left side in FIG. 1) of the first cylindrical member 221. Insert. Thereafter, the permanent magnet 23 and the reinforcing material 24 are inserted, and the holding ring 252 is fitted and fixed to the insertion port side. That is, a pair of rings 251 and 252 are provided at both axial ends of the permanent magnet 23 and the reinforcing member 24 so as to sandwich them. Next, these are fitted into the outer periphery of the relatively thick second cylindrical member 222. Furthermore, the cylindrical member 22 equipped with these members is fitted and fixed to the rotating shaft 21 made of a non-magnetic material. Finally, the permanent magnet 23 is magnetized and the assembly of the rotor 10 is finished.
The permanent magnet 23 is made of NdFeB, SmCo or the like as a main raw material, and the reinforcing member 24 is made of carbon fiber reinforced plastic (hereinafter abbreviated as CFRP).
The permanent magnet type rotating electrical machine including the stator 10 and the rotor 20 is driven to rotate by supplying three-phase AC power to the three-phase winding 13 from an inverter (not shown) according to the magnetic pole position of the permanent magnet 23. Generate power.
As shown in FIG. 2, the magnetic flux φ of the permanent magnet type rotating electrical machine configured in this way passes through the following magnetic path. First, considering the outside of the permanent magnet 23, it passes through the magnetic path gap including the reinforcing member 24 between the rotor 20 and the stator 10, reaches the stator yoke 11, rotates the stator yoke 11 180 degrees, Return to the south pole of the permanent magnet 23. Further, since the rotating shaft is not a magnetic body inside the permanent magnet 23, the magnetic flux emitted from the N pole of the permanent magnet 23 passes through the cylindrical member 22 of the magnetic body and returns to the S pole of the permanent magnet 23. For this reason, the magnetic characteristics and thickness of the cylindrical member 22 greatly affect the flow of the magnetic flux φ.
Considering ultra-high speed rotation, it is desirable to keep the diameter of the rotor 20 as small as possible to keep the centrifugal force small. However, in order to give the desired magnetic flux φ to the stator 10, first, the thickness PMt of the permanent magnet 23 is determined, and thereby the outer diameter (radius is SHt) of the rotor 20 is also determined. Therefore, the thickness CCt of the cylindrical member 22 inside the permanent magnet 23 and the radius SHt of the rotating shaft 21 are matched, but if the radius SHt of the rotating shaft 21 is increased, the rotation is stabilized and high speed operation exceeding the resonance point is possible. It becomes. However, when the thickness CCt of the cylindrical member 22 is reduced, the magnetic flux φ is insufficient, and the torque of the motor or the generated power of the generator is insufficient. For this reason, if the rotary shaft 21 is made of a high-strength nonmagnetic material such as Inconel, the radius SHt can be reduced to some extent, and the thickness CCt of the cylindrical member 22 can be secured.
The permanent magnet type rotating electrical machine having the above configuration is easy to assemble, improves productivity, and is free from waste, so that it can be reduced in size and weight.
FIGS. 3 and 4 show examples of different magnetization of the permanent magnet 23. In an ultra-high speed rotating electrical machine, the permanent magnet 23 is magnetized in two poles so that high-speed rotation can be obtained without increasing the drive frequency of the inverter. FIG. 3 shows radial magnetization that is magnetized in the radial direction, and FIG. 4 shows hullback magnetization that is magnetized in one direction.
In the radial magnetization shown in FIG. 3, the magnetic flux φ shown by the broken line flows through the magnetic cylindrical member 22 because the magnetic magnetization is radial from the center of the circle, but the magnetic cylindrical member 22 is not present inside the permanent magnet 23. Magnetic flux flow is greatly hindered.
On the other hand, since the magnetic flux is magnetized in one direction in the Hullback magnetization of FIG. 4, even if there is no cylindrical member 22 of the magnetic material inside the permanent magnet 23, the magnetic flux φ can flow to some extent. However, in this case as well, when the magnetic cylindrical member 22 is inside, the flow of magnetic flux is improved as shown by the broken line.
As can be seen from the figure, the magnetic characteristics and thickness CCt of the cylindrical member 22 greatly affect the flow of the magnetic flux φ. Along with this, the induced electromotive force IV decreases, and the main factor is that the magnetic flux density in the magnetic material tends to be saturated. When the magnetic flux density in the magnetic material is saturated, the magnetic flux φ of the permanent magnet 23 cannot be used effectively. Compared with the case where the rotating shaft 21 is made of a magnetic material, a level at which the induced electromotive force IV does not decrease much, and an induced electromotive force ratio IVR of 90 [%] or more is required in practice.
Here, according to the experiment results of the inventors, the results shown in the graphs of FIGS. 5 to 8 were obtained. This experiment evaluated the utilization factor of the magnetic flux φ generated by the permanent magnet 23 by measuring the induced electromotive force IV induced in the stator winding 13 when the rotor 20 is rotated at a constant speed. It is. In addition, the value when the rotating shaft 21 is made of a magnetic material as in the prior art is set as a reference value (100 [%]), and the ratio to this reference value is shown as the induced electromotive force ratio IVR [%].
FIG. 5 is an example of hullback magnetization, and the horizontal axis is a graph of the induced electromotive force ratio IVR [%] with respect to the ratio of the thickness CCt of the cylindrical member 22 and the thickness PMt of the permanent magnet 23. From this graph, it is understood that the ratio of the thickness CCt of the cylindrical member 22 and the thickness PMt of the permanent magnet 23 is 1.0 or more because the induced electromotive force ratio IVR is obtained about 90 [%] or more. Further, the induced electromotive force ratio IVR of approximately 100 [%] is obtained when the ratio of the thickness CCt of the cylindrical member 22 and the thickness PMt of the permanent magnet 23 is 1.17 or more, as shown in the figure. In the embodiment shown in FIGS. 1 and 2 described above, the thickness CCt of the cylindrical member 22 is 24 [mm], and the thickness PMt of the permanent magnet 23 is 6.5 [mm]. Therefore, the cylindrical member thickness CCt / magnet thickness PMt on the horizontal axis is about 3.7, and the induced electromotive force ratio IVR is almost 100% as shown by the broken line in the figure.
FIG. 6 is a graph of the induced electromotive force ratio IVR with respect to the ratio of the thickness CCt of the cylindrical member 22 and the radius SHt of the rotating shaft 21 on the horizontal axis in the same example of hullback magnetization. From this graph, it is understood that the ratio of the thickness CCt of the cylindrical member 2 to the radius SHt of the rotating shaft 21 is 0.25 or more that the induced electromotive force ratio IVR is obtained about 90% or more. In addition, it is understood that the ratio of the thickness CCt of the cylindrical member 2 and the radius SHt of the rotating shaft 21 is 0.37 or more that the induced electromotive force ratio IVR is obtained approximately 100%. In the embodiment shown in FIGS. 1 and 2 described above, the thickness CCt of the cylindrical member 22 is 24 [mm], and the radius SHt of the rotating shaft 21 is 8 [mm]. Accordingly, the cylindrical member thickness CCt / rotating shaft radius SHt on the horizontal axis is 3.0, and the induced electromotive force ratio IVR is almost 100% as shown by the broken line in the figure.
FIG. 7 is a graph of the induced electromotive force ratio IVR with respect to the thickness of the cylindrical member 22 along the horizontal axis in the example of the Hullback magnetization. From this graph, it can be seen that the induced electromotive force ratio IVR of about 90 [%] or more is obtained when the thickness CCt of the cylindrical member 2 is 7.2 [mm] or more. In addition, it can be seen that the induced electromotive force ratio IVR is substantially 100 [%], and the thickness CCt of the cylindrical member 2 is 10 [mm] or more. In the embodiment shown in FIGS. 1 and 2 described above, the thickness CCt of the cylindrical member 22 is 24 [mm]. Therefore, as shown by the broken line in the figure, the induced electromotive force ratio IVR is almost 100%.
FIG. 8 is an example of radial magnetization, and the horizontal axis is a graph of the induced electromotive force ratio IVR with respect to the ratio of the thickness CCt of the cylindrical member 22 to the radius SHt of the rotating shaft 21. From this graph, it is understood that the ratio of the thickness CCt of the cylindrical member 2 to the radius SHt of the rotating shaft 21 is 0.8 or more that the induced electromotive force ratio IVR is obtained about 90% or more. Further, it can be seen that the ratio of the thickness CCt of the cylindrical member 2 and the radius SHt of the rotating shaft 21 is 1.27 or more that the induced electromotive force ratio IVR is obtained almost 100%. In the embodiment shown in FIGS. 1 and 2 described above, the thickness CCt of the cylindrical member 22 is 24 [mm], and the radius SHt of the rotating shaft 21 is 8 [mm]. Accordingly, the cylindrical member thickness CCt / rotating shaft radius SHt on the horizontal axis is 3.0, and the induced electromotive force ratio IVR is almost 100% as shown by the broken line in the figure.
As described above, by using a high-strength material such as non-magnetic material Inconel for the rotating shaft 21 and using the magnetic cylindrical member 22 between the permanent magnet 23 and the rotating shaft 21, the primary resonance point is exceeded. Ultra-high speed rotation is possible. In addition, a permanent magnet type rotating electrical machine having a small size and light weight and excellent productivity can be obtained by effectively using the magnetic flux φ of the permanent magnet 23. In the embodiment shown in FIGS. 1 and 2, the primary resonance frequency of the rotating shaft 21 is 340 [Hz], and the corresponding rotation speed is 20400 [rpm]. In this embodiment, Ultra-high speed rotation of 40000 [rpm] or more was obtained.
FIG. 9 is an axial sectional view showing a schematic structure of a turbine generator using a permanent magnet generator according to an embodiment of the present invention. The generator 100 is a permanent magnet type rotating electrical machine having the structure described with reference to FIGS. 1 and 2. The stator 110 includes a three-phase winding 113 on a stator yoke 111. The rotor 120 includes a non-magnetic rotating shaft 121 and two bearings 101 and 102 at positions where the rotor 120 is sandwiched in the axial direction. The non-magnetic rotating shaft 121 is overhanged and extends rightward in the drawing, and the blade 201 of the compressor 200 and the blade 301 of the gas turbine 300 are attached to the overhang portion 1211. The gas turbine 300 rotates when compressed gas is sprayed onto its blades 301. At this time, in order to increase the degree of compression of the compressed gas, the temperature is increased by recompression by the blades of the compressor 200, and then the compressed gas is guided to the blades 301 of the turbine.
Thus, the gas turbine generator is configured, and the blade 201 of the compressor 200 and the blade 301 of the gas turbine 300 are attached to the non-magnetic rotating shaft 121 of the permanent magnet generator 100. This lightweight and strong integrated rotating shaft 121 can realize a turbine generator that is small and lightweight and has excellent productivity.
The compressor 200 and the turbine 300 are often operated at high temperatures in order to increase efficiency, and non-magnetic materials are often used for these rotary shafts as materials that can withstand high temperatures. Therefore, it is not always necessary to integrate the rotating shafts of the permanent magnet generator 100, the compressor 200, and the turbine 300, and the rotating shafts of nonmagnetic materials may be connected to each other. In this case, if the rotating shaft 121 of the permanent magnet generator 100 is a non-magnetic material such as Inconel, the rotating shafts of the compressor 200 and the turbine 300 are also non-magnetic materials, so that the coupling is simple and the production efficiency is improved. .
Further, in FIG. 9, the turbine generator is also connected to the turbine 300, but the permanent magnet type rotating electrical machine 100 may be used as an electric motor and only the compressor 200 may be driven. In this case, it is possible to obtain an air compressor that is small and light, has excellent productivity, and stably rotates at a high speed.

  According to the present invention, it is possible to obtain a permanent magnet type rotating electrical machine, an air compressor, and a turbine generator that effectively use the magnetic flux of the permanent magnet, are small and light, have excellent productivity, and stably rotate at high speed.

Claims (14)

A stator with armature windings;
In a permanent magnet type rotating electrical machine equipped with a permanent magnet attached via a magnetic body fixed to a rotating shaft of a nonmagnetic body that rotates inside, and provided with a reinforcing material that holds the permanent magnet on the outside thereof,
An outer first cylindrical member that forms the magnetic body, and an inner second cylindrical member that is thicker than the first cylindrical member;
Insert the cylindrical permanent magnet into the first cylindrical member, insert the cylindrical reinforcing material further outside, and sandwich the permanent magnet and the reinforcing material between both ends of the axial direction, Fit and fix a pair of retaining rings,
Thereafter, the first cylindrical member is fitted on the outer periphery of the second cylindrical member to form a magnetic cylindrical member,
A permanent magnet type rotating electrical machine, wherein the magnetic cylindrical member is fitted and fixed to the rotating shaft of a non-magnetic material.   2. The permanent magnet type rotating electrical machine according to claim 1, wherein the permanent magnet is magnetized by hullback. The permanent magnet type rotating electrical machine according to claim 1, wherein the thickness of the magnetic cylindrical member is equal to or greater than the thickness of the permanent magnet. 2. The permanent magnet type rotating electrical machine according to claim 1, wherein the thickness of the magnetic cylindrical member is 0.25 times or more of the radius of the rotating shaft. 2. The permanent magnet type rotating electrical machine according to claim 1, wherein the thickness of the magnetic cylindrical member is 7.2 [mm] or more.   2. The permanent magnet type rotating electric machine according to claim 1, wherein the permanent magnet is radially magnetized. 2. The permanent magnet type rotating electrical machine according to claim 1, wherein the thickness of the magnetic cylindrical member is 0.8 times or more the radius of the rotating shaft.   The permanent magnet type rotating electric machine according to claim 1, wherein the permanent magnet is mainly made of NdFeB or SmCo. A stator with armature windings;
In a permanent magnet type rotating electrical machine equipped with a permanent magnet attached via a magnetic body fixed to a rotating shaft of a nonmagnetic body that rotates inside, and provided with a reinforcing material that holds the permanent magnet on the outside thereof,
An outer first cylindrical member that forms the magnetic body, and an inner second cylindrical member that is thicker than the first cylindrical member;
The cylindrical permanent magnet is inserted into the first cylindrical member, the cylindrical reinforcing material is further inserted outside the first cylindrical member, and sandwiched between both ends of the permanent magnet and the reinforcing material in the axial direction. Fit and fix a pair of retaining rings,
Thereafter, the first cylindrical member is fitted on the outer periphery of the second cylindrical member to form a magnetic cylindrical member,
A permanent magnet electric motor in which this magnetic cylindrical member is fitted and fixed to the rotating shaft of the non-magnetic material;
An air compressor comprising a compressor coupled to a rotating shaft of the electric motor.   10. The air compressor according to claim 9, wherein the rotating shaft is a non-magnetic material integrally formed across the electric motor and the compressor.   The blade of the compressor according to claim 9 or 10, wherein two blades arranged at two positions sandwiching the rotor of the electric motor, and a non-magnetic body integrally formed on the rotation shaft overhanged from these bearings, An air compressor characterized by being installed. A stator with armature windings;
In a permanent magnet type rotating electrical machine equipped with a permanent magnet attached via a magnetic body fixed to a rotating shaft of a nonmagnetic body that rotates inside, and provided with a reinforcing material that holds the permanent magnet on the outside thereof,
An outer first cylindrical member that forms the magnetic body, and an inner second cylindrical member that is thicker than the first cylindrical member;
Insert the cylindrical permanent magnet into the first cylindrical member, insert the cylindrical reinforcing material further outside, and sandwich the permanent magnet and the reinforcing material between both ends of the axial direction, Fit and fix a pair of retaining rings,
Thereafter, the first cylindrical member is fitted on the outer periphery of the second cylindrical member to form a magnetic cylindrical member,
A permanent magnet generator in which this magnetic cylindrical member is fitted and fixed to the rotating shaft of the non-magnetic material,
A compressor and a turbine connected to the shaft of the generator;
A turbine generator, wherein a rotor of the generator, a blade of the compressor, and a rotating shaft connected to the blade of the turbine are made of a non-magnetic material.   The turbine generator according to claim 12, wherein the rotating shaft is a non-magnetic material integrally formed across the generator, the compressor, and the turbine.   14. The compressor blade according to claim 12, wherein two bearings disposed at two positions sandwiching the rotor of the generator and a non-magnetic body integrally formed on the rotating shaft overhanging from the bearings And a turbine generator to which blades of the turbine are attached.

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