JP2000134839A - Permanent-magnet rotor and electric machine therewith - Google Patents

Abstract

PROBLEM TO BE SOLVED: To drastically improve the cooling performance of a rotor by arranging a reinforcing member while dividing it into at least two portions in the direction of the rotary shaft of the rotor. SOLUTION: Cylindrical permanent magnets 3a-3f are arranged in the direction of the shaft of a rotor at the outer-periphery part of a solid shaft 2 made of steel of a magnetic material. Then, cylindrical reinforcing members 4a and 4b made of carbon fiber reinforced resin (CFRP) are arranged at the outer- periphery part of the permanent magnets 3a-3f. Also, an annular member 6 made of a nonmagnetic metal material is fitted between the permanent magnets 3a and 3d. Further, annular members 5a and 5b made of a nonmagnetic material for preventing the leakage of magnetic flux and for protecting the end face of the permanent magnets 3a-3f are fitted to both the ends in the direction of the shaft of the rotor of the permanent magnet 3 and the reinforcing members 4a and 4b. In this manner, the part of the rotor 1 that is not covered with CFRP is divided into two portions and a metal annular member 6 is installed at the center, thus allowing heat generation inside the rotor to effectively escape to the outside.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a permanent magnet type rotor and a rotary electric machine using the same, such as an electric generator or a motor.

[0002]

2. Description of the Related Art As a permanent magnet type rotor used for a rotating electric machine such as an electric generator or an electric motor, for example, JP-A-6-284
No. 609, Japanese Patent Application Laid-Open No. 8-107641, and US Pat.
No. 68390 is known. In these rotors, permanent magnets such as rare earth magnets are arranged around the rotor shaft, and around these permanent magnets, at least over the entire length of the permanent magnet portion of the permanent magnet rotor, a cylinder made of fiber-reinforced resin or the like is provided. A reinforcing member having a shape is provided.

In a rotating electric machine having such a permanent magnet type rotor, a rare earth magnet having a high energy density is used as a permanent magnet in order to realize a higher speed and a larger capacity. In addition, a cylindrical reinforcing member is installed around the rotor to apply the centrifugal force of the permanent magnet with the increase in speed, and a high-strength fiber-reinforced resin is used as the reinforcing member. In addition, wind loss generated in the gap between the rotor and the stator due to high-speed rotation of the rotor, and heat generated by copper loss and iron loss in the stator are caused by passing cooling gas through the gap between the rotor and the stator. Cooling.

[0004]

In order to realize high-speed and large-capacity storage, neodymium-iron-boron or samarium-cobalt rare earth magnets having a high energy density are used as permanent magnets, but these are ferrite magnets. Unlike that, the electric resistivity is small. For this reason, the eddy current generated in the permanent magnet due to the harmonic component contained in the magnetic field passing through the rotor is large, and the loss increases as the speed and capacity increase. Furthermore, carbon fiber reinforced resin (C
FRP) is often used, but since CFRP has conductivity, an eddy current also occurs in the reinforcing member. As described above, when there is a loss, that is, heat generation inside the rotor, the fiber-reinforced resin coating the outer peripheral portion of the rotor has a low thermal conductivity, so that the heat generation inside the rotor is efficiently transferred to the cooling gas. However, there has been a problem that the temperature of the rotor rises, the magnetic properties of the permanent magnet deteriorate, and the strength of the reinforcing member made of fiber reinforced resin decreases.

An object of the present invention is to provide a permanent magnet type rotor having a structure capable of efficiently cooling, and an electric machine having the same.

[Means for Solving the Problems]

According to the present invention, there is provided a permanent magnet rotor having a permanent magnet disposed on an outer peripheral surface of a shaft and a cylindrical reinforcing member disposed on the outer peripheral surface of the permanent magnet. Disclosed is a permanent magnet type rotor that is divided into at least two or more parts in a rotation axis direction.

Further, the present invention discloses an electric machine using the above-mentioned permanent magnet type rotor.

Further, according to the present invention, a cooling gas introduction passage for ventilating a cooling gas is provided in the stator in a gap between the stator and the rotor, and the cooling gas blow-out port from the introduction passage is provided with the cooling gas outlet. An electric machine configured to be located at a divided portion of a reinforcing member is disclosed.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a one-side longitudinal sectional view showing a first configuration example of a permanent magnet type rotor according to the present invention. FIG. 1 schematically shows the structure of the rotor, and the detailed structure of each part including both shaft ends is omitted. FIG.
, A permanent magnet type rotor 1 is an example of a rotor of a two-pole synchronous motor, and a steel solid shaft 2 made of a magnetic material and six shafts are arranged on the outer periphery of the shaft 2 in the axial direction of the rotor. The main part is constituted by the cylindrical permanent magnets 3a to 3f provided, and the cylindrical reinforcing members 4a and 4b made of carbon fiber reinforced resin (CFRP) disposed on the outer periphery of the permanent magnets 3a and 3f, respectively. ing. A ring-shaped member 6 made of a non-magnetic metal material is mounted between the permanent magnets 3c and 3d. Furthermore, at both ends of the permanent magnet 3 and the reinforcing members 4a and 4b in the rotor axial direction,
Ring-shaped members 5a and 5b made of a non-magnetic material are mounted to prevent leakage of magnetic flux and protect end faces of the permanent magnet.

As the permanent magnets 3a to 3f, neodymium-iron-boron based rare earth magnets capable of obtaining a high magnetic flux density are used. Further, the permanent magnets 3a to 3f are sintered anisotropic magnets having a cylindrical shape and an axis of easy magnetization oriented in a radial direction, and are two-pole magnetized. Reinforcing members 4a, 4
“b” is made of CFRP in which high-strength carbon fibers are wound substantially perpendicularly to the rotor axis direction, and applies the centrifugal force of the permanent magnets 3a to 3f accompanying the high-speed rotation of the rotor 1. CF
As the matrix resin of the RP, a resin having high heat resistance is used in consideration of a temperature rise due to heat generation of the electric motor.

In the permanent magnet type rotor as described above,
If the rotational magnetic flux generated by the stator winding contains a harmonic component, the magnetic flux passing through the rotor fluctuates as described above, and an eddy current is generated on the outer periphery of the permanent magnet 3 and the shaft 2. This causes eddy current loss and generates heat inside the rotor.
In the case of a rotor whose outer peripheral portion is covered with CFRP as a reinforcing member, the thermal conductivity of CFRP is as small as 1.0 W / (m · K), that is, it is difficult to transfer heat generated inside the rotor to the outside. If there is heat generated by the permanent magnet or CFRP
, The magnetic properties of the permanent magnet and the strength of the CFRP decrease. In order to solve this problem, in the configuration shown in FIG.
By dividing and installing a metal ring-shaped member 6 at the center, heat generated inside the rotor is effectively transmitted to the outside. The material of the ring-shaped member 6 is a non-magnetic material in order to avoid bypass of magnetic flux, and a titanium alloy having a high specific strength for a high peripheral speed. The thermal conductivity of the titanium alloy is 6.6 W /
(M · K), and a greater cooling effect can be obtained for CFRP.

FIG. 2 shows an example of the construction of an electric machine using the permanent magnet type rotor of FIG. 1. A longitudinal section of a centrifugal compressor constructed by installing centrifugal impellers at both ends of a rotating shaft of a permanent magnet type electric motor. FIG. In FIG. 2, an electric motor 101 at the center of a compressor 100 includes a rotor 1 having a permanent magnet 3 arranged in a cylindrical shape on the outer periphery of a shaft 2, and further having a reinforcing member 4 therearound, and a stator 10. Have been. As the permanent magnet 3, a neodymium-iron-boron based rare earth sintered magnet having a high magnetic flux density is used. In addition, high-strength CFRP is used for the reinforcing member. The structure of these rotors is the same as in FIG.

The rotor 1 has radial bearings 11a and 11b.
And axial bearings 12a and 12b, and centrifugal impellers 13a and 13b are attached to both shaft ends. The electric motor 101 has an intermediate duct 15 substantially at the center of the stator 10 in the rotation axis direction.
A ring-shaped member 6 made of metal is provided on the surface of the rotor 1 corresponding to
Is installed. Here, the area of the intermediate duct 15 is mainly determined by the required flow rate of the cooling air and the flow rate is, for example, 5 to 10 m /
However, it is preferable from the viewpoint of the cooling effect that the width of the metal ring-shaped member 6 in the axial direction is also substantially equal to the width of the intermediate duct 15. However, if the width of the ring-shaped member 6 is too large, the length of the rotor, and hence the length of the electric machine, is increased. Therefore, it is preferable that the width be as small as possible within a range where a sufficient cooling effect can be obtained. According to the example, e.g.
About 10%.

As described above, since the ring-shaped member 6 is located at the cooling air introduction portion and is in contact with the low-temperature cooling air, the heat generated inside the rotor passes through the ring-shaped member 6 rather than the CFRP coating portion having poor heat conductivity. Cooled efficiently. Further, while passing through the gap between the rotor 1 and the stator 10, the cooling air introduced into the electric motor takes out windage and other heat, and is then exhausted outside the machine. Thus, the temperature of the cooling air, that is, the ambient temperature of the rotor, is lowest at the center of the rotor, which is the cooling air introduction part. In FIG. 2, the intermediate duct 1
Although there is only one 5, the axial position is the same as that of the duct 15 in FIG. 2, and the cooling effect can be further enhanced by arranging a plurality of them in the circumferential direction of the shaft.

FIG. 3 is a one-side longitudinal sectional view showing a second example of the construction of the permanent magnet type rotor according to the present invention. Note that FIG.
Schematically shows the structure of the rotor, and the detailed structure of each part including both shaft ends is omitted. This permanent magnet type rotor 1A is also an example of a rotor of a two-pole synchronous motor, and has a solid steel shaft 2 made of a magnetic material and a rotor The main part is constituted by six cylindrical permanent magnets 3a to 3f arranged in the axial direction. However, unlike the configuration of FIG.
a and 3f have carbon fiber reinforced resin (CFR)
No cylindrical reinforcing member made of P) is provided.
Further, the permanent magnets 3c and 3d are arranged at a predetermined interval, and nothing is fitted into this portion of the shaft 2,
It is a space. According to this structure, the reinforcing member made of CFRP having poor thermal conductivity is divided and arranged in the axial direction,
By exposing the shaft surface, heat generated inside the rotor can be transmitted to the outside without being insulated by CFRP, and the cooling performance of the rotor can be improved. Further, the configuration is simpler than that of FIG.

FIG. 4 is a one-side longitudinal sectional view showing a third structural example of the permanent magnet rotor according to the present invention. FIG.
Schematically shows the structure of the rotor, and the detailed structure of each part including both shaft ends is omitted. This permanent magnet type rotor 1B is also an example of a rotor of a two-pole synchronous motor, and has a solid shaft 2B made of a magnetic material such as steel as in the case of FIG.
And six cylindrical permanent magnets 3a to 3f arranged in the rotor axis direction on the outer periphery of the shaft 2B, and carbon fiber reinforced resin (CFRP) arranged on the outer periphery of the permanent magnets 3a and 3f. Cylindrical reinforcing member 4
A main part is constituted by a and 4b. However, unlike the configuration of FIGS. 1 and 3, the shaft 2B has a protrusion 7 near the center of the outer peripheral portion, and permanent magnets 3a to 3c and 3d to 3f are arranged on both sides of the protrusion 7 therebetween. Thus, the permanent magnets 3 c and 3 d are in contact with both end surfaces of the projection 7. A ring-shaped member 5a made of a non-magnetic material is provided at both ends of the permanent magnet 3 and the reinforcing members 4a and 4b in the rotor axial direction in order to prevent leakage of magnetic flux and protect the end face of the permanent magnet as in the configuration of FIG. , 5b are mounted. According to this structure, similarly to the configuration example of FIG. 3, the reinforcing member made of CFRP having poor heat conductivity is divided and arranged in the axial direction.
By exposing the shaft surface, heat generated inside the rotor can be transmitted to the outside without being insulated by CFRP, and the cooling performance of the rotor can be improved.

FIG. 5 is a one-side longitudinal sectional view showing a fourth embodiment of the permanent magnet type rotor according to the present invention. This figure also schematically shows the structure of the rotor. The detailed structure of each part including the same is omitted. This permanent magnet type rotor IC is also an example of a rotor of a two-pole synchronous electric material. A solid shaft 2 made of steel, which is a magnetic material, and six outer circumferential portions of the shaft 2 are arranged in the axial direction of the rotor. Cylindrical permanent magnets 3a to 3f
A main part is constituted by cylindrical reinforcing members 4a, 4b and 4c made of carbon fiber reinforced resin (CFRP) arranged on the outer peripheral portions of the permanent magnets 3a and 3f, respectively. However, in this configuration example, the permanent magnets 3a to 3f are divided into three, and metallic ring-shaped members 6a and 6b are provided between the permanent magnets 3b and 3c and between the permanent magnets 3d and 3e.
Are provided so that heat generated inside the rotor can be effectively transmitted to the outside.

It goes without saying that the rotor having the configuration shown in FIGS. 3 to 5 described above can be used as the rotor of the electric machine shown in FIG. Also, in the configuration examples of FIGS. 1 and 3 to 5, the rotor of the two-pole synchronous motor has been described, but the type and the number of poles of the electric machine are not limited thereto.
The number and material of the permanent magnets and the reinforcing members are not limited to the present embodiment, and the same configuration is possible. Any number and material may be used as long as the gist of the invention can be realized. Furthermore, in each configuration example, the CFRP is installed so as to cover the axial width of the permanent magnet. However, if the CFRP is divided and a structure capable of dissipating heat is provided between the CFRPs, the cooling effect is improved. The axial widths of the CFRP and the permanent magnet do not necessarily have to match as long as the performance is not impaired.

[0019]

As is apparent from the above detailed description, according to the present invention, the cooling of the rotor is achieved by dividing the reinforcing member into at least two parts in the direction of the rotation axis of the rotor. This has the effect of greatly improving performance.

[Brief description of the drawings]

FIG. 1 is a one-side longitudinal sectional view showing a first configuration example of a permanent magnet rotor according to the present invention.

FIG. 2 is a longitudinal sectional view showing a configuration example of an electric machine using the permanent magnet type rotor of FIG.

FIG. 3 is a one-side longitudinal sectional view showing a second configuration example of the permanent magnet type rotor according to the present invention.

FIG. 4 is a one-side longitudinal sectional view showing a third configuration example of the permanent magnet rotor according to the present invention.

FIG. 5 is a one-side longitudinal sectional view showing a fourth configuration example of the permanent magnet rotor according to the present invention.

[Explanation of symbols]

 1, 1A, 1B, 1C Rotor 2, 2B Shaft 3a, 3b, 3c, 3d, 3e, 3f Permanent magnet 4, 4a, 4b, 4c Reinforcement member 5a, 5b Ring member 6, 6a, 6b Ring member 7 Shaft protrusion 10 Stator 15 Intermediate duct 100 Centrifugal compressor 101 Motor unit

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Hideo Nishida 603, Kandamachi, Tsuchiura-shi, Ibaraki Pref. Inside the Tsuchiura Plant, Hitachi, Ltd. (72) Naohiko Takahashi 603, Kandamachi, Tsuchiura-shi, Ibaraki, Japan Within the Tsuchiura Plant (72) Inventor Yasuo Fukushima 603, Kandamachi, Tsuchiura-shi, Ibaraki F-term in the Tsuchiura Plant, Hitachi, Ltd.F-term (reference) PP07 PP11 PP17 PP18 PP19

Claims (5)

[Claims] 1. A permanent magnet is arranged on an outer peripheral surface of a shaft,
Further, in a permanent magnet rotor in which a cylindrical reinforcing member is disposed on the outer peripheral surface of the permanent magnet, the reinforcing member is divided into at least two or more members in a rotation axis direction of the rotor. Features a permanent magnet rotor. 2. The permanent magnet type rotor according to claim 1, wherein a metal ring-shaped member is provided between the divided reinforcing members. 3. The permanent magnet is also divided where the reinforcing member is divided to form a divided portion, and a brim-shaped convex portion formed as a part of a shaft is arranged in the divided portion. The permanent magnet type rotor according to claim 1, wherein the rotor comprises: 4. An electric machine using the permanent magnet type rotor according to claim 1. 5. A cooling gas introduction passage for ventilating a cooling gas in a gap between the stator and the rotor is provided in the stator, and a cooling gas outlet from the introduction passage is provided for the reinforcing member. The electric machine according to claim 4, wherein the electric machine is configured to be located at the divided portion.