CN203166647U - Electric rotating machine - Google Patents

Abstract

An object of the present invention is to provide a rotating electrical machine including a permanent magnet synchronous motor whose power density and reluctance torque are increased to improve efficiency. The rotating electrical machine includes an embedded magnet rotor (10) in which a permanent magnet (5) is embedded in a core of a rotor (10), and the cross section of the permanent magnet (5) is concave from the rotor outer diameter side to the rotor inner diameter side, wherein A part or a plurality of parts of the first magnetic body (6) constituting the rotor core is constituted by a second magnetic body (7) having a higher magnetic permeability than the first magnetic body (6).

Description

rotating electrical machine

technical field

The utility model relates to a rotary electric machine which requires small size and high output especially in the applications of compressors, HEVs, EVs, and fuel cell vehicles, and particularly relates to a permanent magnet synchronous motor. the

Background technique

In recent years, since the supply of rare earth magnets is insufficient, the demand for rare earth-free motors has increased especially for small motors. For this reason, electric motors mounted on EVs, HEVs, and fuel cell vehicles, represented by compressors used in air conditioners and refrigerators, are also seeking both rare-earth-free and high-efficiency miniaturization, including a reduction in the amount of magnets used. the

As a method of increasing the power density of the permanent magnet synchronous motor, in addition to utilizing the magnet torque generated by the magnetic flux of the magnet, there is also a method of effectively utilizing the reluctance torque generated by the difference in inductance of the rotor. The reluctance torque is determined by the saliency ratio Lq/Ld of the d-axis inductance Ld and the q-axis inductance Lq, and the reluctance torque becomes larger as the saliency ratio increases. the

The smaller the magnetic resistance R is, the easier it is for the magnetic flux to flow. The magnetic resistance R is determined by the shape and permeability of the elements forming the magnetic flux path, and is expressed by (1) formula. the

R=l/(μ·μ ₀ S)...(1)

Among them, l: the magnetic path length of the element, S: the magnetic flux cross-sectional area of the element, μ: the relative magnetic permeability of the element, μ ₀ : the magnetic permeability of vacuum. According to the formula (1), the larger μ and S are, the smaller the magnetoresistance becomes.

FIG. 6 shows a perspective view of a permanent magnet type rotor described in Patent Document 1. As shown in FIG. The permanent magnet type rotor described in Patent Document 1 shown in FIG. 6 is configured such that a rotor 10 composed of a first magnetic body 6 has a magnet insertion hole 4, and a magnetic block 3 and a permanent magnet 5 are inserted into the rotor so as to overlap in the thickness direction. Insert the magnet into hole 4. The magnetic block 3 is any one of a magnetic material having a high saturation magnetic flux density, or a magnetic material having a high magnetic permeability due to a high magnetic flux density. That is, having the magnetic block 3 having a higher permeability than the first magnetic body 6 reduces the reluctance R in the magnetic block 3 , so that the reluctance torque can be found without reducing the magnet torque. the

Prior art literature

Patent Documents

Patent Document 1: Japanese Patent No. 3871873

Problems to be solved by the utility model

There are two technical problems in prior art document 1. the

One is the reluctance torque. The reluctance torque depends on the inductance saliency ratio of the d-axis and the q-axis, that is, the magnitude of Lq/Ld. The d-axis 1 and the q-axis 2 of Patent Document 1 are shown in FIG. The increase of the pole ratio is also small, and the increase of the reluctance torque is small. the

In addition, as another technical problem, there is a case where the effect of improving the power density is small. As shown in formula (1), the reluctance decreases due to the increase of the magnetic flux cross-sectional area S and the relative magnetic permeability μ, so when the cross-sectional area of the second magnetic body is increased, the power density will increase accordingly. Increase. In the structure like Patent Document 1, it is difficult to ensure the cross-sectional area of the magnetic body. the

Utility model content

An object of the present invention is to provide a rotating electrical machine including a permanent magnet synchronous motor whose power density and reluctance torque are increased to improve efficiency. the

solution

A rotating electrical machine has a magnet-embedded rotor in which permanent magnets are embedded in a rotor core, the permanent magnets have a concave cross-section from the outer diameter side of the rotor to the inner diameter side of the rotor, and a part or more of the first magnetic bodies constituting the rotor core The first part is composed of a second magnetic body having a higher permeability than the first magnetic body. the

utility model effect

According to the present invention, it is possible to provide a rotating electrical machine including a permanent magnet synchronous motor whose power density and reluctance torque are increased to improve efficiency. the

Description of drawings

Fig. 1 is an axial sectional view of a rotor of a permanent magnet synchronous motor according to a first embodiment of the present invention. the

Fig. 2 is an axial sectional view of the rotor of the permanent magnet synchronous motor according to the first embodiment of the present invention. the

Fig. 3 is an axial sectional view of the rotor of the permanent magnet synchronous motor according to the first embodiment of the present invention. the

FIG. 4 is a graph showing the relationship between magnetic flux density and magnetic permeability in a magnetic body. the

Fig. 5 is an axial sectional view of the second embodiment of the present invention. the

FIG. 6 is a diagram showing a permanent magnet type rotor as background art. the

Reference signs are explained as follows:

1 d axis

2 q axis

3 magnetic block

4 magnet insertion hole

5 permanent magnets

6 The first magnetic body

7 second magnetic body

8 Magnetic poles

9 The second magnetic body insertion hole

10 rotors

12 ribs

13 Leakage Flux Path

14 slots

15 Advanced side

16 Lag side

Detailed ways

Hereinafter, embodiments of the present invention will be described with reference to the drawings. the

[Example 1]

Fig. 1 shows a rotor axial sectional view of a permanent magnet synchronous motor based on a first embodiment of the present invention. The rotor 10 is composed of a first magnetic body 6 , a plurality of magnet insertion holes 4 concave from the rotor outer diameter side to the rotor inner diameter side are arranged, and permanent magnets 5 are provided in the magnet insertion holes 4 . The permanent magnet 5 is inserted into the magnet insertion hole 4, and like the magnet insertion hole 4, its cross section (section perpendicular to the rotation axis of the rotor) has a concave shape from the rotor outer diameter side to the rotor inner diameter side. That is, the permanent magnet 5 has a concave shape curved such that the central portion is away from the outer peripheral surface of the rotor or close to the rotation center side with respect to both circumferential end portions. In addition, a second magnetic body insertion hole 9 is provided on the inner diameter side of the rotor of the permanent magnet 5 , and has a structure including the second magnetic body 7 here. The second magnetic body 7 is a magnetic body material whose magnetic permeability is higher than the first magnetic body 6, because the magnetic permeability of the second magnetic body 7 is larger than the first magnetic body 6, so the reluctance of the second magnetic body 7 is according to ( 1) Formula reduction. Thereby, the magnetic flux density in the second magnetic body 7 increases, and the power density improves. In addition, in the example of FIG. 1 , Lq is increased by arranging the second magnetic body 7 on the q-axis 2 . On the other hand, since Ld does not change, the salient pole ratio increases, and the reluctance torque also increases. the

In addition, since the second magnetic body 7 is arranged in the middle of two adjacent permanent magnets 5, and is arranged on the inner diameter side with respect to the permanent magnet 5 having a concave shape from the outer diameter side of the rotor to the inner diameter side of the rotor, it is easy to secure the permanent magnets. 5 configuration spaces. Therefore, the cross-sectional area (thickness in the radial direction) of the second magnetic body 7 can be increased. the

FIG. 2 shows an example of changing the arrangement of the second magnetic body 7 . In FIG. 1 , while the second magnetic body 7 is arranged on the q-axis 2 , the second magnetic body 7 is arranged on the magnetic pole portion 8 where the magnetic flux concentrates. The magnet insertion hole 4 is formed integrally with the second magnetic body insertion hole 9 , and the second magnetic body 7 is held by the magnet insertion hole 4 . The permanent magnet 5 in FIG. 2 is also the same as the permanent magnet 5 in FIG. 1 , because its cross-sectional shape is concave from the rotor outer diameter side to the rotor inner diameter side, so the magnetic pole portion 8 of the second magnetic body 7 is arranged. The area (cross-sectional area) of the second magnetic body 7 is ensured to be large, so the cross-sectional area (thickness in the radial direction) of the second magnetic body 7 can be increased. the

According to this structure, the effect of increasing the magnetic flux density by the second magnetic body 7 becomes large, and the power density improves. Since the magnet insertion hole 4 and the second magnetic body insertion hole 9 are integrally formed, there is no need to ensure a gap between the second magnetic body insertion hole 9 , so that the power density can be increased without reducing the magnetic resistance in the rotor. the

In addition, when a permanent magnet having a coercive force of 1000 kA/m or less is used, the magnetic pole portion 8 operates with a low magnetic field. As shown in FIG. 4, by setting a magnetic body having high permeability in a low magnetic field, such as an amorphous body and a nanocrystal (Finemet), as the second magnetic body 7, the magnetic flux increases even when the magnetomotive force of the magnet is small. , the power density is increased. Figure 3 shows this embodiment. In this case, the leading side 15 in the rotation direction of the magnetic pole portion 8 is composed of the first magnetic body 6 , and only the lagging side 16 is composed of amorphous and nanocrystals on the second magnetic body 7 . Compared with the leading side 15, the magnetic field becomes smaller on the lagging side 16, so it can operate in a state where the magnetic permeability of the second magnetic body 7 is high. the

The first permanent magnet 5 may be a sintered magnet mainly composed of rare earths, or may be formed of a bonded magnet, or may be formed of a ferrite magnet or an alnico magnet. In addition, the first permanent magnet 5 may be an integrated permanent magnet of the same type, or a plurality of divided permanent magnets may be arranged axially or circumferentially. The first permanent magnets 5 may be one magnet of the same type or different types of magnets. The first permanent magnet has a curved shape, but may also have an I-shape or a U-shape. The second magnetic body 7 may be held by the magnet insertion hole 4 as shown in FIG. 2 , or may be formed and held by the second magnetic body insertion hole 9 as shown in FIG. 1 . In FIG. 2 , the second magnetic body 7 is in the shape of a semicircle, which may be a circle, may also be formed by an arc, may be a quadrangle, or may be a polygon. There is one second magnetic body 7 for each pole, but it may be divided into a plurality. The rotor consists of six poles, but any number of poles may be used as long as it has two or more poles. the

[Example 2]

Fig. 5 shows an axial sectional view of the rotor of the permanent magnet synchronous motor according to the second embodiment of the present invention. The basic structure of the rotor is based on Example 1, so the description is omitted. The rib 12 (refer to FIG. 1 ) facing the end of the permanent magnet on the outer peripheral side of the rotor is composed of the second magnetic body 7 , and the second magnetic body 7 extending in the circumferential direction of the rotor outer peripheral portion is held by the groove 14 provided in the rotor 10 . The permanent magnet 5 in FIG. 5 is also the same as the permanent magnet 5 in FIG. 1 , and its cross-sectional shape is concave from the rotor outer diameter side to the rotor inner diameter side. At this time, the end portion of the permanent magnet 5 on the rotor outer peripheral side is configured to follow the rotor outer peripheral surface. the

In this structure, a material whose magnetic permeability becomes low in a high magnetic field is used as the second magnetic body, such as an amorphous body. When the magnetic field of the rib 12 is 100 A/m or more, the magnetic permeability of the amorphous body becomes lower than that of the electrical steel sheet. Since the magnetic flux hardly flows through the ribs 12 in the magnetic saturation state, the leakage magnetic flux 13 generated in the rotor outer peripheral portion can be reduced, and the torque ripple can be reduced and the output can be improved. In addition, in the case where the rib 12 is formed as a hole and when the rib 12 is made of a non-magnetic material, the same effect can be obtained for reducing the leakage flux, but it is different from a non-magnetic material and a hole. Since it is a magnetic body, it can operate without obstructing the magnetic flux path of the magnetic pole part 8. the

The first permanent magnet 5 may be a sintered magnet mainly composed of rare earths, a bonded magnet, or a ferrite magnet or an alnico magnet. In addition, the first permanent magnet 5 may be an integrated permanent magnet of the same type, or a plurality of divided permanent magnets may be arranged axially or circumferentially. The first permanent magnets 5 may be one magnet of the same type or different types of magnets. The first permanent magnet has a curved shape, but may be I-shaped or U-shaped. The shape of the outer periphery of the rotor is maintained by providing grooves 14 as shown in FIG. 2 , but it may be molded with resin or the like without providing grooves, or may be retained by SUS tubes, etc., or a magnetic body insertion hole may be provided in the first magnetic body 6 9, and insert the second magnetic body 7. The rotor may also have more than two poles, and any number of poles may be used. the

Claims (7)

1. A rotating electrical machine comprising a magnet-embedded rotor in which permanent magnets are embedded in a rotor core, wherein the permanent magnets have a concave cross section from the rotor outer diameter side to the rotor inner diameter side, wherein: A part or a plurality of parts of the first magnetic body constituting the rotor core is composed of a second magnetic body having a higher permeability than the first magnetic body. 2. The rotating electrical machine according to claim 1, wherein: A part or a plurality of parts of the first magnetic body constituting the rotor core on the outer peripheral side of the permanent magnets are formed of a second magnetic body having a higher permeability than the first magnetic body. 3. A rotating electrical machine according to claim 2, wherein: The rib, which faces the end of the permanent magnet on the outer peripheral side of the rotor and is formed of a magnetic body extending in the circumferential direction, is formed of a second magnetic body. 4. A rotating electric machine according to any one of claims 1 to 3, characterized in that, The magnet insertion hole for embedding the permanent magnet and the insertion hole for inserting the second magnetic body consist of one hole. 5. The rotating electrical machine according to claim 2, wherein: A part or a plurality of parts on the hysteresis side of the magnetic pole portion are made of the second magnetic body. 6. The rotating electrical machine according to claim 3, wherein: The second magnetic body portion doubles as a magnet hold down. 7. The rotating electrical machine according to claim 3, wherein: The second magnetic body is a magnetic body having high magnetic permeability in a low magnetic flux density region.

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